I play multiplayer all the time, and I'm not gonna just blow smoke up your ass.
Turrets actually have some viability now. Some people are raving over the TEC turret, and that's fine, but if you like to play vasari, I promise you their turret upgrade kicks ass. It stops all hull, shield, and antimatter regeneration for a LONG time (something like 10 minutes?). It actually has a pretty major effect on something like a capship or an invading vasari starbase (those are the things you want to make sure to target with this thing). You just have to be judacious with how to use turrets. Don't just spam them everywhere. If I know a planet is gonna be invaded, and I'm vasari, I sprinkle a couple of these things around where the phase jump will come in, to make sure at least 1 of them can't be avoided. When the enemy arrives I make sure to manually target the turret or turrets onto his capships and invading starbase (if there is one). All it takes is one hit, and that cap is gonna be crippled. If you have a decent fleet defending, it means he has to retreat the caps that are affected fairly shortly in the battle, or he is gonna lose them.
Some will disagree, but I think mines are overpriced. Plus, there is an exploit where you can avoid them with the Z axis. I think these issues need to be fixed.
The other starbases are good, but again you don't just spam them mindlessly, and they have to have PROPER SUPPORT or they will die. Just to give you an example, I was in a game a few weeks ago. A guy I see online fairly reguarly named "Aquila" or something like that was on the losing side, and all his other teammates had been defeated. He was Advent and invited us to all gang up on his super Advent starbase, and then he'd quit after the fireworks were over (he wasn't being a dick - he also said he'd quit if we didn't accept his challenge). We accepted. I myself had a maxed out vasari fleet. My 2 teammates fleets were close to maxed out on slots, if not maxed out. We jumped in with all our fleets at the same time and went for the starbase and focus-fired it together. Surprisingly, we all lost everything. He had repair, upgraded hangers, plus those synergizing advent turrets. We thought that since we had such overwhelming late game fleets, we could mindlessly attack, but we couldn't. Anyway, I definately see other starbases besides vasari used online in real games by "pro" types, so they are viable in the right situations. Thing is, don't scream and whine if you leave an unupgraded starbase sitting there with no hanger or carrier protection, and it goes down to some bombers in 30 seconds.
As others have said, the vasari phasic trap hanger upgrade is excellent - I always get it if the situation calls for it and I have the labs and money and time to deploy it. It is so good that if anything it is OP rather than UP (no, I'm not calling for a nerf!). Try it. Especially good at defending your vasari starbase from bombers. If you have everything deployed right, your starbase will essentially be immune to bombers.
The flak turrets you want are now on TEC hangers, if you upgrade them.
By the way Dorian, I think I remember you from a long way back (not sure). If you are who I think you are, CARRIER SPAM IS NO LONGER A PROBLEM. Flak works now (on fighters), plus carrier speed was nerfed so they can't just kite around the edge of the grav well (other aspects of the carriers received nerfs too), and there was a substantial buff to LF so they can catch and kill the carriers.
Also, some capships (especially carriers) received substantial buffs! They are quite fun to play now, and you actually see a heck of a lot more capships being built and used online now, and not just marza for TEC either (in fact, the dominant cap for TEC is now the sova, believe it or not). Many of us are hoping the devs buff some of the other capships in the next patch.
The game plays quite differently than the last time you were here, so you'll have to get used to a few things. Make sure to try out the new capships (sova is excellent now, kortul is a monster, akkan now has #1 colonize in the game). Just to keep you from being blindsided online, watch out for the advent dual halcyon rush, watch out for seeker/disciple spam, and in general watch out for carrier capital ship spam (mostly advent).
If you need some practice games online just to try stuff out, send me a PM.