An elevator maze in the center... lol jk
Hmm... how about players can pick teams? They vote FFA 3v3 2v2 1v1 4v4 2v2v2v2 3v3v3, or uneven 1v2 3v2 4v3 whatever (on uneven everyone has to agree) and then they divede up (step on becon for team). Hard terraining i suppose lol.
No teching, tomes need to stay as back-up for max heros and not be too good, or not be at all, items should be better. Mabey you can buy Merc.? Their cool...
Changable enviorments, trees that grow! As baby trees they can be choped down and slow unit movement but are not sight blockers, as medium trees they stop unit movement can be choped down and partialy obscure unit sight (Oculer Height thingy) As large trees they are sight blockers and movement blockers that can be choped down. Mabey rocks? They can be blown up, or melted with fire then they turn into a little pool of lava which hurts units, lol. Weather effects that slow movement, rain hail, and ice makes units go faster and slide (ok to much yes i know but still, im just gathering ideas). Gaint milk bottles appear! They block movement and heal units when you open them with huge lakes of yummy milk! Ok im gonna stop, this is getting a little far "out-there"...