Quote Originally Posted by Grod_The_Giant View Post
Remember that concentration means something different in 5e than it did in 3.5-- namely, it no longer takes an action.
This is a major point I missed in the OP. Only a few spells require round-after-round actions, and most of those are either really strong damage/debuffs or are super weak. Most of the time, you put up a concentration spell (for the big fights) and then focus on blasts, prompt debuffs (non-concentration but only last one round) or cantrips.