The magic system would also need rewriting from scratch.

Also, the "whole side moves at once" system is quite appropriate for a system representing battle-lines and ranked formations of troops.

For example if alernating activations are used a single unit might step forward from the battle-line, intending to be followed by the others, but get singled out and flank charged for exposing itself, whereas in reality the whole battle-line would step forward together, with the flanks at no time exposed.

Unlike 40k fantasy does offer an interesting tactical challenge, mainly due to the bonuses for flank and rear charges, and the ability to flee from charges and set up favourable overruns etc to expose the enemy unit's flanks. Unfortunately over the last couple of years a major "codex-creep" has set in leading us back to the bad-old-days of "herohammer", where hugely powerful characters and monsters sweep ranked troops aside, and an overpowered magic phase being a game-winning rather than enhancing tactic, which has removed some of the tactical nuance of the game.