I think the biggest bugaboo is the rebels getting out of the trench to charge an exploding AT-AT and getting themselves killed from the shockwave and debris (though the explosion is still cool - and yeah, I always figured the crash damaged the armor around the neck - still would like to see some shooting form the roof windows to add some life to the model).

I have no idea how this can make any sense - I understand keeping the "snowspeeder shooting the AT-AT to pieces" scene, but what about the "C'mon!" and the troops get out of the trenches with the snowspeeders overhead? Could that shot be replaced by rebels simply cheering in the trenches (and staying under cover) with snowspeeders flying overhead?