But to refresh your memory (and anyone else who might care why 4e doesn't have the Spellcaster problem):
* All Classes are on the same, unified resource schedule scheme (AEDU). Character resources no longer have power discrepancy and refresh discrepancy that the game must be awkwardly balanced around (which introduces all of the other things like Magical Arms/Races, Rock/Paper/Scissors, and Calvinball GMing to block spellcasters).
* The most powerful Spells in classic D&D are siloed to Rituals. Rituals are (a) costly, (b) everyone has access to them, (c) they aren't usable in combat except very specific situations, and (d) they're almost exclusively a tool for either (i) reframing and/or transitioning scenes (as 4e is a scene-based game) or (ii) to invoke the fictional positioning necessary to allow for a Skill Challenge (to open up a scene that would otherwise be presently unavailable to the players).
* Everyone can get access to the Skill Arcana.
* The game is fully scene-based and Noncombat Conflict Resolution is the organized like Clocks in World/Forged in the Dark games or the Conflict mechanics of Mouse Guard et al. The Skill Challenge is a scene with an inherent dramatic arc and discrete gamestate moments that follows pretty much the exact same indie GMing ethos that is being espoused in this thread; play to find out, say yes or roll the dice, follow the fiction, follow the players lead (and react), genre logic, change the situation (after each moment of action resolution), and fail forward. The framework, the maths, and the GMing ethos means that Martial answers to gamestate problems are just as potent and reliable as Arcane/Divine/Primal answeres to gamestate problems.