I have played at Rise of Legends and I noticed that huge armise does not cause lags. Maybe you should see that game. I think Big Huge Games combine 3D models and 3D sprites. Maybe you should test this idea?
How can I switch-off replays? I'm afraid some day I found gigabytes of files filled by replayses. And I also wait that day when Atlas Manual will be standalone from internet connection. Thank you!