As the kind of guy who likes to number crunch and find break-even points and really get under the skin of the game's mechanics, these are four technologies that really irk me. They're not particularly useful, they're overshadowed by other much simpler and cost-effective alternatives, and in general can be ignored. With the exception of refineries, I have never used any of these in a multiplayer game. They need considerable help to enter the world of usefulness, and I have my own ideas of what can be done.
#1) Colony Pods
I had a little bit of trouble deciding which upgrade takes the cake for “most useless economic upgrade”, but I eventually settled on colony pods. First of all, it's a starbase upgrade, so you need to have a starbase (something very expensive and totally non-viable as a purely economic installation). It uses up one upgrade slot on that starbase, precluding other potentially necessary upgrades. So right off the bat there are lots of hurdles to using colony pods.
Even not counting the cost of the starbase, the colony pods themselves are exorbitantly expensive, priced the same as usual starbase upgrades (1800 credits, 275 metal, 150 crystal). For a measly 1.3 credits per second, this is not a good deal at all. In fact, it's overshadowed by the trade port upgrade which grants a minimum of 1.6 credits per second. In other words, even if you don't have a trade route at all, the trade port upgrade is better. Don't even get me started on the second level, which is ridiculously expensive and offers a pinch more cash.
Now, colony pods do have an upside: they can only be destroyed by destroying the starbase. Trade ports can be destroyed by bombers and the planet's population can be decimated by siege frigates. However, this argument is fairly weak since we're talking about a starbased gravity well.
How should colony pods be improved? The best option, in my opinion, would be to dramatically reduce the upgrade cost. The fact that they require a starbase and take up precious upgrade slots is a huge price to begin with, and even the monetary cost is simply out of this world compared to the benefits. A cost of around 500 credits (making it very cheap by starbase upgrade standards) might be appropriate. Although that may seem low, it's actually still inferior to what a moderate-high loyalty planet will give you in tax income from a population upgrade. Remember that the real cost is the starbase and its upgrade capacity!
#2) Resource Focus
This upgrade is as close to garbage as you can get (though I eventually decided colony pods were slightly worse). I've found a few theoretical cases where it might be worthwhile, but the amount of effort to make it work just isn't worthwhile when you can spam trade ports for almost the same effect.
The simple question a player must ask himself is whether it is more profitable to leave a trade port as a trade port, or to convert it for resource focus. For this example, I'll presume a nearly worst-case scenario for the trade port user: I'll use the 4.5 conversion rate and a (very) low estimate of 1.6 credits per second from each of your trade ports. By these numbers, you'd need 0.35 resource per second benefit in order for converting to resource focus to be worthwhile. With basic unupgraded resource focus granting an 8% boost, the planet would need a base resource income of 4.375 just to break even with what could be achieved with trade port operation. This value is utterly unachievable; basic resource focus is literally never useful.
Even if you do have the 7-lab level upgrades (we're talking about a 7th lab level upgrade here; this is end-game material!) it's still not that strong. Your trade port is likely very long by now, so let's give a (very) low-ball estimate of 2.4 credits per second income each. Again, using the 4.5 conversion rate, we require 0.53 extra resources to break even. With the 25% boost... we need approximately 2 resource income per second from the planet to be worthwhile. This is break-even condition is only possible on absurdly high-loyalty planets with 4 rocks. In other words, you need allure of the unity and induced reverence to make it work. You're better off just making your trade route longer to boost credit income, since you get so little from converting to resource-focus mode.
How should resource focus be improved? I think we can agree that resource focus should be useful only on planets with 3-4 rocks and high to very high loyalty. It should be competitive with moderate to long trade routes (with respect to what stage of the game we're in). With that in mind, I'm going to look at an 80% loyalty planet with 3 rocks and as the break-even condition. Such a planet's base resource income is 1.2 per second.
With an early-game trade route estimated at 6 jumps, this gives trade ports an income of 1.9 credits per second. With this as our target break-even, a little algebra tells us what the base extraction bonus of resource focus should be 35%. This should only serve to demonstrate how underpowered the current resource focus (at 7%, capping at 25%) really is.
Next, a late-game example for the resource focus upgrades. Let's up the trade route to 9 jumps and 12 jumps for our break-even comparison. That gives trade port income at 2.5 and 2.9 respectively, mundane as far as the late game goes. Using the same approach as before, we get extraction bonuses of 46% and 53%. Let's round that off to 45% and 55%, which are nice clean numbers.
That is where I think it should be: basic resource focus at 35% bonus, improving to 45% and 55% with its 7-lab upgrade.
#3) Vasari Volcanic Population Upgrade:
Appearing later in the tech tree than any other population upgrades, and being the most expensive as a result, it's surprising that these upgrades pack so little effect. The problem is that volcanic planets have very little population to begin with, and so even a large %-based modifier doesn't translate into significant absolute values.
Even if you max out the upgrade, it only gives you +60% population. This would be nice on any other type of full-sized planet, but the volcanic has only 70 population to begin with. You get a measly 42 extra population per planet for completing the upgrade line (a mere 10 population per upgrade), with two techs at the 4th level and two techs at the 5th level. This is a very expensive high-level tech that gives quite little in return and requires you to have a silly amount of volcanics.
While it is possible to have a large number of volcanics, you'd need 9 or 10 for this to be seriously worthwhile. Even presuming one in three of your planets is a volcanic (a ridiculously high proportion; I've never seen it happen), this implies an empire approximately 30 planets large, which is large enough that it should have a trade-based economy rather than a tax-based economy. By the time this upgrade is viable, it's no longer relevant.
How should volcanic population upgrades be improved? Simple: like the upgrades for terrans, deserst, and ice planets, the volcanic population upgrade should be viable for only a handful of volcanics. With that in mind, 30/60/90/120% would be reasonable modifiers. Even when maxed out, that's only 84 extra population per planet (21 per upgrade level). This is approximately on par (in an absolute sense) with the terran planet upgrades that come much earlier in the tech tree.
I've listed a lot of junk above. I'm sure a lot of the multiplayer guys were just nodding their heads in agreement; these are things we just never see. Refineries are in a different class. Not so much useless as use-impaired. There are situations where they work, quite well even. The problem is, those situations are few and far between and in the long-run it's hard to compare to the glory of a long trade port chain.
The upshot of refineries is that (unlike resource focus) they can affect multiple planets. If you get a good junction, you might have 6 planets under the effect of a single refinery, averaging 3 extractors each. This means there are some great scenarios that just scream for refineries. The problem is that these situations are rare and far between. The average case situation leaves few viable locations for refineries and most of the time it's simpler and more cost-effective to go with trade ports.
Even if you do go for refineries on a larger scale, their effect caps off in an annoying manner that can cause two stacks of refineries in close proximity to conflict with each other. As well, trade ports just become better and better as your empire grows, while refineries don't scale. While not useless, refineries have a lot of problems, and the kicker is that they cost twice as much as trade ports.
How should refineries be improved? Seriously, just lower their cost. Move them to the same cost-range as trade ports and they'll be fine. If they were less expensive and could be deployed more easily, people would get them a lot more often. They don't have to be the best thing in the world, but they do need a little bit more edge.
That's my four cents on four sub-par economic technologies in this game.