Lanefan
Victoria Rules
Which is fine, as there's some inherent limitations that mean the wizard (or cleric) isn't going to be able to pull it off every time and their being able to pull it off some of the time is quite OK, and is a large part of what makes playing those classes fun.Really good post Lanefan!
I think we actually have a fair amount of agreement here (eg Clerics should get folded in with M/Us...particularly in 2e...and it gets worse in 3.x and 5e) while the disagreements are pretty nuanced. So to get to that:
* I see where you're going with the "Obstacles/Problem Areas generally need to become increasingly multidimensional as you go up in level." And I agree (generally). The issue with this approach is "contact with the enemy." The "enemy" here is two-fold; very clever Wizard players and the potency of higher level spells (or a single “big gun” matched with a level 1 supplementing spell to achieve a particular gambit) and their ability to neutralize that multi-dimensionality by fundamentally rewiring/reorienting the fiction.
The limitations:
- the caster's player won't always recognize or realize that the situation could be solved with a particular spell, and-or won't connect the dots to the point of finding that spell in time for it to matter. Usual result: either someone else solves the Obstacle/Problem by other means or it remains unsolved
- the character might not have the key spell prepared, or (less commonly but is still happens) might be in one way or another out of gas, or in some cases might not know the spell at all (e.g. the adventure is written on the assumption someone in the party has Knock as a spell, but no-one does). Usual result: either a delay in solving the Obstacle/Problem until the caster can re-load spells, or it gets solved by other means, or it remains unsolved
- the enemy might take action to prevent the caster from casting, or to interrupt it. In the systems we're talking of, spell interruption is a thing; so a wise enemy might make use of archers or other disruptive effects to hinder casting
Personally, I don't often find either of these issues to be a major problem. The game IME isn't as fragile as you seem to be making it out, and frequently has to handle sudden and massive changes in PC power both up and down. Just last night, for example, my party got hit by a couple of lightning bolts and after a series of unfortunate rolls both front-liners now have no armour left! The party's resilience and combat ability just took a serious kick in the you-know-wheres, but the game can handle it without me-as-DM having to change anything about the adventure as written. (whether the PCs can handle it remains to be seen, but the game itself has no problem with it!)* The problem with "the magic item solve" for the disparity between martials and casters is that the use-cases of sudden jumps in utility prowess are quite limited and focused (like Flying Boots) and its a rather fine line when balancing via magic item usage. The game is extremely sensitive to it...and the game is sufficiently fragile such that the other side of that fine line often equals broken.
The other issue with that "the magic item solve" is the default game already involves too much (and increasingly so as levels pile on) cognitive workload and handling time for GMs. Adding more isn't a great answer!

Same thing if they find some really powerful item - almost without exception the game can handle that sudden increase in capability quite well; or so I've found over time, at least.
As for the cognitive-load issue, I figure that just comes with the territory of trying to run high-level games. That said, it's on the players to worry about their characters' items, not on me.
