if you don't like to play that way, don't.
I don't see the situation quite as [MENTION=87792]Neonchameleon[/MENTION] does, maybe because I'm more willing to tweak the ingame fiction and allow that perhaps, even though the rules say so, my particular wizard isn't capable of learning
all those spells.
On the other hand, I haven't GMed a system without systematic spell list limits (Rolemaster, 4e D&D) for many many years. And when I last played a cleric in D&D (2nd ed AD&D) it was pretty broken, even though I had a less than optimal sphere set.
And anyway, I strongy sympathise with Neonchameleon at least to this extent: if the game breaks when a player pushes it even moderately hard, something has gone wrong. If choosing Web, Glitterdust, Evard's and Polymorph breaks the game, then they shoudn't be in the game in the first place - at least as a permitted combo, if not invidivudally.
Spells as equipment makes complete sense, however when I play a fighters, i usually try mix up the weapon/armour complement between my different fighter characters.
For me, the difference is this: Optimising across fighting styles is mathematically challenging, and highly dependent on the sorts of foes faced. Some builds are obviously weak, I think (1st level fighter, leather armour, low DEX, dagger). But others are potentially competitive (eg a low level fighter trading a bit of AC for improved manoeuvrability doesn't strike me as obviously irrational - there are no full attacks to be lost by moving, for example).
Whereas working out that Evard's is broken is a no-brainer.
I bet the people with the caster problems have DM's who don't actually flex their DM muscles and stop the 15 minute work day and the hundreds of magic shops r us.
It's not MUs who need magic shops. They can get buy with their spell load-out plus a few darts. (And, in 3E, with the items that they make themselves.) It's fighters who need magic shops, or some other way for acquiring the magic weapons, armour etc that are essential for their high level viability (as has been discussed in this and other recent threads).
I think some people expect, certainty in 4th editions case, that combat is the end all to the D&D game.
This is a complete red herring. In AD&D MUs are also broken in social engagements (Charm, Suggestion, ESP) and at exploration (Knock, Detect . . ., Fly, Inivis, etc).
I don't get the 'even divination' makes a caster so powerful. What divination spells? In general, divinations only help out in bland one track railroad adventures.
This is not remotely true. In any sort of rich campaign world, being able to learn stuff - who loves or hates whom, who is working for whom, who did what, who was where when - is hugely valuable.
My first long-running Rolemaster camaign broke down in part under the weight of a well-played diviner.
Divination magic works better in a sandbox than on a railroad. You don't scry for people who want to attack you (normally). You scry for people who you want to attack.
In that same campaign, but at lower levels before it broke down, the PCs used to do this using magic detection! (They were somewhat mercenary, and big fans of the magic item resale market.)
the more these discussions go on, the more I wonder if they aren't solely creations of the internet as a medium.
In my own case, I experienced MU overshadowing of others in the first AD&D game I GMed (in 1984-85). And that was even in a game involving two-handed swords against the giants, with a 10th level ranger!
It was also a big factor in the above-mentioned RM campaign. In my second long-running RM campaign we nerfed a few things, and made various agreements in PC building, to prevent it being such a big issue.
To date, in 4e it's not been a problem. (And the campaign is currently at 15th level.)