KA is decent. Infected isn't bad until the last boss aside from a nigh impossible optional objective. (Really, all the ground optionals should flat out reward a second EDC to everyone.) The Cure is not for PuGs on any difficulty; they ought to let everyone bring a full away team to this one to put the focus on the strategy and then just beef up the Elite mode mobs to account for there being 25 friendlies on hand.
I think this will be a good soulution if u get to bring your away team because i havnt completed the ground cure and I tend to avoid it.
I think a good alternative would be to mark the objective complete even if you fail the optional objectives. In The Cure, only one actual part of the mission requires the use of four or more players. If after the objective failed players were given a chance to just move on, then I think more would stick around, even if the final loot is less as a result.