My group is running a loose campaign using LR/DR units and rules, with the PL Leader rules, scenarios, activation fumbles/crits, and Leader progression rules. They work fine. The only things we changed is Leaders who are reduced model sized units. Those still roll for Lucky Blows and engage in Challenges; If they lose a Challenge or receive a Lucky Blow, they lose their Leader abilities, and their army has to take Courage test. Losing a challenge also reduces the unit by a strength point.
Another point is the +1 for units activating within 12" of the leader. We use it but don't allow it for spell casting. The +1 does change the game, making it go a bit faster. Since we usually play multiplayer games, this is fine, keeps things moving.
It has been great fun. Between Leaders getting captured, scarred, or losing the respect of their troops, and crazy results on the activation tables, lots of stories have been told!