I'd love some of the things aforementioned on this page, but I just wonder if they'd work...
Firstly, Hogsmeade does escape destruction so that'd be okay.
BUT, and here's the crux of the problem, how could any representation of the battle be included without blowing a hole in the timelessness of the land? I thought before opening (and after) people were always talking about how nothing should really take place which 'moves events on' if you see what I mean? I was under the impression that the island is meant to be a single moment in time. Also, how far along would we take this hypothetical destruction of Hogwarts? It may look odd to see it destroyed to the tune of DH Pt 2 destruction, only to step outside again and find all is dandy.
Second problem relates to the new climax of the ride if it was changed. If we changed to a Battle of Hogwarts scene, surely the finale would have to be Harry beating Voldemort? Not only does this have the time period issues described above, I thought WB / JKR didn't want Voldemort in the island at all? Currently there's not so much as a mention of him. If we got the the Battle as a finale and Voldy didn't show, it would be a huge anticlimax.
Although, maybe Uni have reason to include some darker elements / characters... Have any exit surveys addressed this kind of thing? I would imagine quite a few people are left disappointed by lack of Voldemort at the moment.
And I do agree, it could well be that FJ was intended to be updated from it's inception... A certain scene currently full of non-functioning dementors could be very useful for the Battle of Hogwarts, and there isn't much in the way of physical sets in that scene, so it could be pretty simple to bring in something new...