What would be COOL!
-------------------
Allow more than 1 player per side.
Each player may only control their assigned force.
This would include some command co-ordiantion challenges.
You might also have a key leader unit for each player. Elimination of this unit would introduce some command-control difficulties.
What would be LAME!
-------------------
Please don't do an RTS/Simul-turn based combo as previously mentioned. It just ain't worth it!