Well, you can still click a unit’s avatar in the sidebar to immediately select that unit, or you can shift-click a unit to deselect it (remove it from the group). This simplifies the separation of ‘healthy’ vs ‘wounded’ units a bit.
The general strategies against the AI seem to be:
1) Build your base while defending against attacks using tactically placed melee units with archers behind them (combine with towers if you wish).
2) Build 2-3 groups of super-tough units and send them to destroy the enemy bases bit by bit.
On land I’d mostly use Ogres / Ogre Mages (Knights / Paladins). If the enemy has fliers, then also include some trolls / archers in the group.
On sea maps I would use groups of destroyers, or juggernauts/battleships once they are available. One word of advise, though – always have a couple of destroyers accompanying your heavy ships in the event of being attacked by fliers – battleships/juggernauts cannot attack air!
Once air units are available, everything else becomes kinda useless – groups of dragons / gryphons can pretty much take out everything the AI throws at you.
