This is what I am seeing, too. You can get most everything done with a strong offensive military - which is a downside to a degree because some of the other technologies are kindof nifty.
Yeah... that's a challenge. I'll have to think on what to do with that. Maybe the AI needs to be stronger on the offensive so that you need more of these technologies in order to defend yourself. Of course, there again, that law of unintended consequences will likely rear its head. This one needs some thought/discussion.
The main issue is that unusual for the genre, to gain knowledge you need offense. And since knowledge is the most important resource, you are going to emphasise what's necessary to gain more knowledge: offensive ships.
Plus one of the more previously irritating problems was how wimpy the defensive turrets were. For wormholes with few attacks they were ok since you'd repair them quickly enough after each assault, but for any real assault (8x special forces base on an adjacent world...) they'd just die, and die, and die, and... even forcefields aren't all that helpful. I found I was better off tossing a couple of space docks on the world, tossing forcefields down around them, and cranking out ships, which is... offensive technology benefited.
(Granted they have more health now, but I haven't had a chance to test that yet.)
In short, for minimally-attacked worlds, there's little need to upgrade from the basic turrets, unless you run out; for heavily attacked worlds, there's no reason to build defensive techniques since your offensive ships work much better.
In that above situation, a fortress or two would be good... except they're hideously expensive in knowledge. Four full worlds of knowledge to get the ability to build expensive buildings that can't be repaired. For that I can get two upgrades to Tech III ships which throws in Tech IV as a bonus if you've got an Advanced Factory; which reminds me I think they really actually should be knowledge upgrades, though probably cheaper then Tech III since there is your original "cost" of getting an advanced factory and defending it is high, maybe 1000 or something each so you're at least forced to think, and/or attack a couple of worlds.
In short:
1) Defense should be cheaper then offense (which they are, slightly, but definitely not in research).
2) Defense should be more robust then offense (which they aren't; SRT I health 23000, shields 600; fighters/bombers/cruisers I health 29000/20000/24000, shields 100/1500/150. Really I don't mind SRTs costing more then a fighter, or missile turrets costing almost as much as a bomber since they do more damage, but they really need at least 3x as much health/shields as they do now to be viable in "real" defense).
3) Defense should be less micromangement then defense (which they are in low contested systems, but a pack of offensive ships is also low-micro in a low contested system...)
Offense of course should be increased; this ties nicely into the problem of seriously overpopulated worlds.
Each world should have a threshold, (for the moment I'll pull numbers out of thin air
), we'll assume that 50+/-20% percent of total number of ships the player has for a Tech I world (of course higher Tech worlds, would have higher thresholds, and there should always be a minimal "max" value). The threshold is checked once every $timedelta, (5+/-2 minutes for variance so every world doesn't proc at the same time), then grabs a small force, say up to 6 ships from every wormhole, or command point and sends them towards the player's wormhole.
You'll get a lighter attack, then say a timed wave, since all the ships will arrive in small groups over time since every point will be a different distance from the nearest player owned wormhole, and but you'll get a much more sustained assault so it'll be slower to repair stuff. This will also help with the ridiculous number of ships that regularly build up on nearby worlds, but there should also be a substantial force available there.
As to the only-offensive-knowledge problem there is another semi-solution, involving creating a new kind of research called something like "defensive optimisation". Basically as you kill ships with your defensive turrets/ships on worlds you have an active command center on (to avoid gaining this sort of stuff from parasited turrets and the like, you really don't want to give them any more bonuses
), you get 0.01 point of "defenseop" per tech level (or whatever, needs balancing depending upon how many ships people kill in a usual game and the like. The "defenseop" then discounts on all defensive technologies, it subtracts from there first at one point per knowledge point, before draining knowledge (this will also help with the very "round" values of knowledge you usually have).
This will also benefit the player being risky and camping beside, say, a Tech IV place, or somewhere with a ton of special forces bases, or just not taking out gates so they get more warps, and thus more assaults.
At the very least, I think I've succeeded in making MORE of the units used in average play compared to a lot of RTS games, but this problem of how to get players to use all the units over the life of their experience with the game is pretty endemic to this genre, I think. I'm pretty experimental by nature, but in AoEIII and even SupCom I tended to try stuff once, and then just stick with what worked to the exclusion of all else. In AoEIII I got very good at building just Musketeers as French (and very occasionally their strong melee horseman), and beating the pants off the AI as a boomer with two or three human allies in a 3x3 or 4x4 game. In SupCom, I did a lot more experimentation and used a lot more of the ships, but I just played as Aeon and by the end was using ONLY tech 2 and tech 3 ships, just skipping tech 1 all together. Out of the other RTS games I've played aside from my own, I think the original Empire Earth and then SupCom did the best job of getting me to experiment around. I think I've mostly duplicated that with the offensive military stuff, but not so much with the defensive tech.
Maybe... maybe there should be some sort of "balanced unlocking" rule. Such as, you can only unlock so many techs in one category before you have to unlock some techs in another category to progress onward. The tech "tree" in Rise of Legends was really limited (4 techs each in 4 categories), but it was cool how it made you only able to get 1 or 2 ahead in any category before having to research something from the others. Perhaps something like this would work here... this probably bears more thought.
Already got way too much verbiage, I might get to thinking about this when my fingers stop hurting from all the typing.