You've got a lot of good stuff going here:
Destructible environment has a ton of awesome gameplay ramifications - no two rounds play out the same way, it's entertaining, it acts as a round closing mechanic (as more of a base is destroyed, the more the computer shield is exposed, meaning a match will draw to an inevitable close), cover is dynamic and therefor so is combat, etc.
If I'm not mistaken, you've set things to only receive damage from one team or the other - very good anti-griefing establishment
The map seems appropriately sized, as you don't want it too big once walls are starting to be taken out, leaving vast plains of death.
Good HUD workaround, until the day when hell frezeth and Valve releaseth support for custom HUD implementation (damnit, they keep adding new ones of their own!), although it seems that splashing damage (I tested this for Demo and somewhat Soldier) can skip through the normal 1-2-3 procedure and blow all of the computers up at once (I think they're still taking the appropriate amount of damage and all, but just in chunks that the interface doesn't catch - dunno if it can be fixed)
I love how you set up the re-capturable shield. That's excellent, right there. You might play around with the capture time on it - but I haven't seen it in multiplayer action yet so I couldn't advise on whether it needs to be longer/shorter/is already perfect because you've been testing it so ignore me and my silliness.
All that said, I only have a couple concerns. Because of how Valve set up phys brushes and doors and such, demo stickies and other projectiles like urine never come to rest on them. It's a little funky to see Jarate bounce off a wall, but hey - I guess you can't really work around that. As someone else suggested, I'd advise getting the computers farther from the spawn by either moving the spawn forward (perhaps into a forward building or below-ground bunker) or moving the computers away (splitting them up does sound interesting - I'd say to two separate points with their own shield and single cp so that teams have to manage attacking/defending multiple areas, but then you lose some indication of how much progress you've made as more of the HUD is taken up, although the gameplay trade-off might be worth it, dunno) so that it doesn't ever feel strictly like a campfest.
Oh, and I like Ten19's suggestion of perhaps more available high ground in the middle, perhaps it could be associated with the perhaps-moved spawn?
I wanna try and make to the next playtest!
