Mmmm I do love destructible environment I liked it in C&C series how you could burn down trees with grenades etc. and people hiding in em would get fried. Anyways some of that stuffs too shiny for me, reminds me of stronghold 2 on max graphics, I couldn't even see what the units looked like just big shiny blobs so I had to turn down the graphics settings.
It'd also be awesome in MMO mode if there was a sort of editor to fully customize defense/traps, different aspects used would have to cost resources, it'd probably take some work to figure out the system but it'd be awesome to attack someone and run into a 100% unique trap noone has ever seen before, it'd also add a major strategic element that requires real cunning. Something I would like to do for example is have a line of archers firing at the enemy then when they get close nuf have some ogres turn some wheels in diff places and walls pop up from the ground, 1 under the archers and 1 behind the enemy, awesome stuff like that.