Actually the notion of a drop down menu for this is the first thing that's come up that I really dislike. That level of fragmentation in the game design is going to make it very hard for you guys going forward, I would think. Every design deciision will impact 5 different play styles built around 5 different mechanics, isn't that something of a nightmare?
I disagree. As long as the mechanics accomplish the same thing (in terms of the four goals Chris put on the previous thread) and there aren't a *huge* number of them, balance *should't* be a big problem. Progress gating and straight planet capture don't address the opening multiple fronts thing directly and so I don't think they're ideal candidates. In fact, the core shield generators really don't either (at least not any more than gating or straight planet capture), since you don't HAVE to hold the planets after you capture them - we have to hope that the incentive not to lose an advanced factory or fabricator is enough to have people hold these planets.
Wingflier's solution is really great; it really seems to address all of the major goals of these AI Defense Systems, assuming that you have to control the planets in order to avoid the AIP increase. You'll need to take and hold territory in order to avoid the AIP increase while attacking homeworlds. Balance here is going to be really tricky initally, but for people who want the most open ended experience, this addresses everything in a very subtle way, which I think is awesome. It forces you to hold a planet, at least temporarily, within a few hops of the AI home, or you're going to have a bad time AIP wise - especially if you lose it!
I had mentioned the shield supression nodes (or something similar) but not as a discrete AI Defense System of their own - that was all you, Chris (unless someone mentioned them)
On the topic of incentives to get ARS's: maybe they should give a tiny amount of bonus knowedge per planet (say, 250 or so), per ARS. That would really add up, but it would also be pretty tricky to get, since you have to do a long range raid to get the ARS and then you have to bring it back to your "core" to get the k-bonus! (Of course, that could be solved by making them perma-cloaked or tough as nails or something like that...)
I'd like to re-lobby my idea of turning the shield generators into a mini-scripted campaign of sorts, where instead of blowing shield generators, you're just capturing ARS to figure out how the shield works and then figuring out how to make a virus to disable the AI shield (by capturing adv. factory + adv. fabricator), and then deploying the virus to disable the shield. This is probably too much work and does the same thing as the shield generators - but it eliminates the extra structures, and it's essentially what the shield generator mechanic reduces to anyways (take a bunch of ARS's, advanced factory, advanced fab, and one of x other random planets. Need to figure out how to work the counter-attack guard post in there... maybe the act of disabling the shield triggers a CPA or AI deep strike counterattack) That said, I find nothing *wrong* with the shield generator mechanic; I just think this is a little more interesting flavor-wise. Also, I find the idea of dumping a virus into the AI to disable the shield really cool.
Of the ideas on the list now, the ones I like best are shield generators (ideally with a modification that makes *forces* the player to hold a small bit of territory) and supression nodes. Wingflier's idea needs a name but I could see playing with that too.