Considering my gaming group are all busy people who have family and Job commitments that sometimes get in the way of playing, we have run many 3E games where we were missing a roll.
It normally works out even with published adventures.
Yes the Psion, Warlock, Artificer combo we had one session made some combats hard, but you can adapt. In the case above they figured they were the most deadly at range, so they worked extra hard to take advantage of the terrain to give them the max time before anyone closed on them. (Ambushs from on top of buildings, sniping while hidden, Shoot and Scoot, etc.) It took some creative thinking, but there were strategies that worked.
It's been the same in every edition so far, and I would be very surprised if some creative thinking could not patch most any weakness your group has in 4E.