I've mentioned this before, but, there's an extremely easy mechanic to ensure that strategic considerations stay in the game. Simply create mechanics where the caster chooses a suite of abilities (spells, whatever) for the day. A couple of once/day big guns, a handful of /encounter abilities and a few /round abilities. Poof, done.
There, now, everyone's happy.
Something to remember is that spells are going to be changed. We know that. If nothing else, they'll change in caster level. I can easily see a stream of spells where the wizard gets X, Y and Z of /day, /encounter and /round abilities per day. His spellbook comes in when choosing his suite for the day.