Here's a few ideas I had, I've only ever played at the Site Sporadically and there were a few years worth of gaps - So I'm aware that you may have tried some of this stuff and there may already be a good reason you don't do it and I've just missed it.
1 - I feel like playing the site North to South might be more interesting than East to West? Would mean that in the initial push forward each team get access to a 2 story, plus encourages fighting through the Kill House and Range rather than each one of each typically being controlled by the closest spawning team.
2 - I liked the "Rush" style games you ran in the evening last year - My one gripe on them was when defending being forced to remain in the building. I think that game mode, allow defenders to leave buildings but limit how far forward they can push. Then maybe have a prop in each building that needs defending - Maybe even simulate "Rush" by making the Prop an alarmed countdown timer - with say 15 seconds, so defenders have an window of opportunity to get in and pause the timer if they can remove the attackers.
3 - There's already loads of cover throughout the site which is great, but could always do with more. Or even just a rework of some of the cover to allow some strategic approaches from cover to cover when attacking well defended areas and windows. An area in particular that could do with some extra cover points is just North of building 31, there's often some little engagements up there that could potentially be stretched out and made more challenging with a few more points of cover to run between.
That's all I can think of off the top of my head. But when I next come to a game I'll give it some real thought and see if I can think of anything extra. Curious to hear what others have to say too.
Forum was a great idea too!