Concerning buying up planets.
I ran some tests. Small Galaxy. Three opponents. Cakewalk. CTRL-U to uncover map. CTRL-L to assign colonies. Here's what I found.
Terrans: Buying up planets as the Terrans is doable. A planet with 0 population cost me ~670 bc when buying from the Altarians.
Thalans: I tried buying up a planet as the Thalans. I couldn't do it.
Drath: The Drath have great diplomacy but despite that one planet cost me nearly every penny I had. ~2700 bc.
Custom Race w/ Super Diplomat and 0 diplomacy: Affordable. 870 BC.
Ran game for 2 years. Attempted to buy a planet from Torians while playing the Terrans: No deal.
Conclusion: Super Diplomats can buy planets low population planets for a good price but no one else can. Extra diplomacy helps lower the price. This is a feature not a bug. Considering your economy while buying up planets is a viable option I'd say you could buy two, maybe three planets before you cripple yourself financially.
Ok, maybe it's not a big deal, but for me playing Terrans is challenging only at crippling, because of this feature.
You are right at the start of the game you can buy 2 or 3 planets before you run out of money, but (as Terran) after your planets grow in population, you get republic, and start trading, your economy gets strong.
At that point you have money, and while other races buy ships or improvements, you buy planets. I't not difficult to buy one every ten turns.
If you race for diplomatic translators and that achievement that doubles the value of your diplo offers (can't remember the name) the game is finished.
Thanks anyway for considering this.
Buying planets is NOT a SuperDiplomat feature, you can do it with any race, although it is most easy with humans; also in our CU it became more easy on certain races (while more difficult with others) with the diplo-discrepancies.
First off let me tell you that any test on cakewalk isn't worth a dime because
- the AI isn't fully present.
- the penalties to industry cause newly acquired planets to be less into negative income --> which is the main factor of why the AI wants to trade away planets. While it is true that the same economic penalty applies as well, this is more or less irrelevant because new planets always have low population and can never cover for themselves even at highest difficulty setting. The thing is that on maso, obscene and suicidal core world will cover for these while new planets are far into red income.
I've written it here in this thread many times, the one thing that difficulty setting doesn't speed up is POPULATION GROWTH; while other core stats are increased - these are then responsible to hasten up the game, but the planets will show even less population because the total global population had less time to be grown + distributed.
- You didn't build the Galactic Bazaar... Any experienced player that wants to utilize a diplomacy strategy will leasebuy this wonder ASAP because the bonus to trading far outweighs the leasecosts per turn and it is better than the whole diplo-tree bonuses combined (although it subsequently makes these bonuses even more potent)
Secondly, there are additional factors embedded in the diplomacy (eg trust and respect) which is based on how you treated the AI in the past, courage, racial features and a high MMR also helps greatly, esp. that you can even bully the AI to give planets for free or for peace offering.
Then, if you plan to trade for planets I don't see how you can only trade for 2 or 3 planets??? Without the need to produce colony ships you can go ahead and produce Survey Vessels (if many anomalies are present) and use these to keep everything going. If not you could simply cut down MP and invest more into technology and take advantage of increased racial economic stats, fund yourselfs through techbrokering. If techtrade is disabled then go the social route and fill all planets with market centers. I've played through all of these scenarios and remember games were I bought +50 planets, once it was over I usually had twice the amount of planets than the rest of all AI together combined.
The thing is that [once it is set in motion (you convert your homesystem into a huge techworld and get diplotechs ASAP and use Surveyors to keep yourself running and finding all other AI's) then] it becomes more and more easy the more planets you can acquire every 4/8 turns.
edit:
there are also some trading rules to be observed to make this easy, one is to never offer solely money but instead a mix of techs/bcs (and IP) because this will always net more than if sold separately.
