Firstly, the problem:
- A daily power can never be balanced with a less powerful encounter or at-will power, except by assuming a certain number of encounters per day.
- Similarly, an encounter power can never be balanced with a less powerful at-will, except by assuming a certain number of actions per encounter.
Here are what I see as ways to "solve" the problem:
- Give everyone the same amount of each type of power (4e core).
- Assume a certain number of encounters/actions and enforce at least loose bounds (4e Essentials, 3e with very loose enforcement).
- Have daily/encounter powers be no more powerful than encounter/at-will powers.
- Throw class balance out of the window - or at least make it a low priority.
Perfect opening for me to say again my solution: Do not make daily powers cover the same area as the encounter (or at-will powers). Specifically, in the more refined terms of this topic, do not let daily powers be tactical resources. In the OP, Daztur edged into this a bit in his outline of the wizards' strength and weaknesses.
There are, of course, several ways you can manage that without it being the crude divide of "fancy wizard and cleric spells of immense power will not do tons of damage and/or bypass tactical combat entirely." One of the more obvious is tactical time and position--make direct damage spells or
finger of death type spells difficult but not impossible to set up, whereas things like
wall of stone to cover a retreat should be relatively easy (in casting time and difficulty terms, maybe not in finding the right place to do it or deciding whether or not to do it).
You could also make the strategic spells meant to be used in combat more expensive and/or more expensive when they have the kind of power we associate with daily or limited use resources. For example, I've seen it suggested in various editions were
fireball was thought too powerful or too weak, that it be kept relatively weak normally (so that the wizard not be allowed to steal all the combat thunder), but allow expensive, limited resources to boost it. This is not unlike the 5th level AD&D wizard who finds a wand with 5 charges of an 8th level
fireball, though for our purposes, you'd like the boosting a bit more renewable than AD&D wands.
One of the reasons that daily or other "operational play" resources have been kind of a mixed bag in D&D is that the truly strategic, limited situation-changing options are often inferior to the "just blow up the monsters and be done with it" options. Or I suppose, for things like scry, teleport, and kill--a problem with how the kill happens than the scry and teleport. The wizard with his Save and Die effects is a big part of the kill in that equation. Reverse that balance, and operational play becomes more interesting. Maybe you don't want to scry and teleport--not because this will use up two or three key wizard spell slots, but rather because your wizard isn't all that once you get there--and it is difficult to set up the teleport out if things go pear-shaped.