I think people are misjudging my musings on tier levels across level ranges. I understand tiers to mean as a general ability to resolve arbitrary encounters, meaning, general ability to solve any problem presented to them at their level or slightly above it, or very much above it in some specific cases.
It stands as a fact that casters are very much weaker than meleers in solving encounters until after level 5 or 7, where most good PRC's start kicking in, and full casters get access to 4th level spells and start rocking out on immunities and utility galore. It's also the level where it's starting to pay off using more expensive metamegic, as empower and maximize.
It's also a fact that in general, non-spellcasters (i should've used that generic term on the OP), don't contribute as much for the party after that level as they did before. Because before that, most enemies were nonmagical, had laughable AC and meaningful HP, where the Wizard was limited in spells and couldn't afford to help overcome too much encounters in a meaningful way due to a lack of spells/day and damage, where a dedicated DPS damage-monkey could already be dishing out consistent 30~40 damage nonstop. At that level, not many enemies had meaningful defenses that needed to be pierced or circumvented with magic, and the most meaningful contribution a spellcaster could give is a AC Boost, some SoD's in the form of sleep (which many creatures are immune to), or color spray, limited times per day at a low DC since many monsters have much more HD than CR.
This is how i've always felt the tier system is. The way i see it, it judges the class potential over a 20 level span. Yes, in the long run, the fullcasters will always win the race, just because they have all the options a nonspellcaster has, and then some, but they do start out as turtles(As in the rabbit vs turtle fable, only in this case, after the rabbit starts the nap, the turtle hops in a Mach 10 scramjet experimental airplane and finishes the race and the rabbit awakes to the sound of it and thinks WTF?).
I didn't claim it would reduce a wizard's tier, i just claimed it could maybe increase them for the fighter types, and maybe modify their tier earlier than they would modify a wizard's, thus allowing for non-spellcasters to feel special for longer, all the while making the game a different power level, as the party will certainly be able to withstand encounters far above their EPL, making this a appealing option. But not one without unforeseen consequences. That's why i turned to this board for discussion on such a wildcard variant game.
Yes, nightstick stacking could possibly turn the thing upside down, so it has to be limited in some way, otherwise clerics would just kill off all the wizards and dominate everything with free metamagic up the wazoo. The UMD thing is interesting, and certainly massive checks can be attained easily with competence items of UMD and Cha-Boosting, making Wandmancers more of a threat, and multiple armed wandmancers even more so. So maybe some kind of hard-wired limitation on wands should be applied, lest everyone and their mother becomes a wizard and start rocking out with every spell in the game in the form of Eternal Wands with MAX CL. These are the kind of things that i missed because i stopped to think for 30 minutes on this before posting, but were brainstorming here, brainfarts happen lol. But what about the other, positive, side effects? Could a game with this variant be a fun game for everyone involved?