I like your way of thinking. As has already been brought up your system puts emphasis on shooting and magic because an AoS game of 6 rounds gives your army 12 combat phases in which to fight (because you can also fight in your opponents phases), but only 6 hero phases, movement phases, charge phases and shooting phases.
In your system, your army would only get 6 combat phases in which to fight. Also, just running the combat phase twice in succession or doubling attacks for all units would not solve the problem, because much of the game mechanics revolve around phases lasting only one turn, with only so much damage being dealt, and even more importantly: with re-positioning of units (i.e. a movement phase for one of the players) in between them.
I am not saying this (below) would work, but at least it puts the right emphasis on close combat, and might give you something to work with:
1. Priority phase
2. Hero phase (for both players)
3. Movement phase (Player with priority chooses which army gets to move)
4. Combat Phase (for both players, player with priority gets to activate first unit)
5. Movement phase (The player who didn't move in phase 3, moves now)
6. Combat phase (for both players, player with priority gets to activate first unit)
7. Shooting phase (Player with priority activates first unit, then activates alternate between players until all shooting is done.)
8. Battleshock phase.
Placing shooting after combat might cause some trouble, and it was a tradeoff, Because placing it before movement would ruin some well known game mechanics (like units not being able to shoot if they have run etc..)