First, to everyone asking "why fix what's not broken" - he's just getting feedback; if you don't think there's anything wrong with the current model, that's all you need to say. No need to start trying to tell him what question he should have tweeted out today.
To answer the question:
- I like them because, like in PS1, losing them is the point at which a defender must switch to an offensive gameplay if they hope to stop the base from flipping. I think that's muddied a bit with how capture mechanics have changed, but it's still a very solid "whatever you were doing, its not working, and now you have to try something different".
- Like EvilPig had brought up, I've also been thinking that bringing down the SCU should drop the pain fields and shields on the spawn room. Taking down the SCU should be done so the attackers can remove a source of spawning, not something you do just to make all the defenders hole up in and take pot shots from.
- I'm not sure what I think about having the SCU shields drop at neutral marker, instead of triggered by gen destruction. It does sound interesting, but for me personally that's something I'd need to see / try in action to decide if it felt good or not.
Edit:
And related to SCU's, I think -all- base objectives should have feedback in the game world itself; Like base-wide flood lights that turn on when the SCU is compromised / down, spinning red lights on the building generators are in if it's generator is compromised / down, etc.
I shouldn't have to look at my minimap / map nearly as often as I do to figure what's happening where in a base.