What I'm curious about:
First off, remember that Warlocks don't get that creation ability until level 12. The majority of games are actually played below level 10 (according to various surveys I've seen online) which means that most Warlock players will never even get Imbue Item, so it's weighted a bit less for that reason.
JaronK, if this is weighted, then what does the paladin do in tier 5? Because of course, at the high levels it won't be able to compete with high level spells, but especially at lower and mid levels (definitivly up to lvl 12) it is perfectly capable of fulfilling several roles (face, damage dealer, tank, healer, buffs, debuffs & utility), also several within 1 build. I think this http://brilliantgameologists.com/boards/index.php?topic=10057.0 shows several builds that are capable of that, also with moderate optimization. If it's easier, I can post in the 'why tier 5 are in tier 5' thread a more extensive argument.
Note that "weighted a bit less" isn't the same as not weighted... it's a factor that's considered, but generally speaking I consider 6-15 to be the most important levels to look at (1-5 is most played but the balance differences are also less noticeable in general, while 16+ seems very rarely played). The lower levels of that (6-10) are weighted highest... but I find Paladins have a lot of trouble even relatively early on. They're not great as healers, as their in combat heals are too little to matter and deny them actions, while their out of combat healing is inefficient (especially compared to folks like Binders, Crusaders, Dread Necromancers, etc). MAD is a serious problem for them as well, which reduces their ability to be a face (they need lots of different stats which tends to leave only Dex and Int dumpable... denying them the skill points they'd generally want. Diplomacy is nice but it's likely all they get). As a tank, again that MAD issue makes them worse at this than other high HD heavy armor classes. And there's no way they're going to be able to buff, debuff, and heal on the same character with their limited spell selection, especially in the lower levels, at least not without being very weak in those roles.
In the end, it's hard not to compare the Paladin to the Crusader and see a dramatic difference. Remember that being one Tier apart means the two should still be able to play together well without one completely overwhelming the other. The Crusader, however, will usually make the Pally look pretty silly. Obviously optimization can change this (Battle Blessing is pretty freaking sweet, and Serenity helps a lot) but optimization can pump up the Crusader nicely too. And putting a Crusader in a party with a Paladin is much like having an Unarmed Swordsage with a Monk.
JaronK
But from level 5/6 is where the paladin starts getting crazy multipliers on charge attacks, as well as either the horsy or the charging smite acf. I don't agree with you that crusader and paladin differ that much, against evil opponents the paladin easily outdamages the crusader, even when the latter uses that crazy 8d8 lvl 4 maneuver. Also, I when you compare paladin to monk... they are really in a different level. Monk can do 1 thing and do it badly (combat), paladin can do combat quite good, and as well a bit of other stuff mentioned above. On 'face' role: they have access to diplomacy, gather information, sense motive, as well as some usefull spells annd detect evil. Simply making a paladin that isn't mounted or with a little higher ability score in int., you can make a very good face, especially for a cha based class.
But I'll post later today something in the tier 5 thread.
There's no denying the sheer damage output of the Core combat whores. The math's been done; on a round-per-round basis, an optimized Monk, Barbarian, Fighter, Rogue, and Paladin can all outdamage the Crusader, Warblade, and Swordsage. While the latter three can access similar tricks, the former has more support in splats, and inevitably the sheer numbers add up.
The reason they still rank so low is that's (usually) all they are good at: Dealing damage. The Bo9S 3 are capable of doing things that make the whores cry (Teleportation at will, constant fly speed, jumping Xty feet as a swift action, giving other characters extra turns, etc).
The Paladin's spells don't kick in until post-4th level (and at that point the spells he does get are fairly worthless). Meanwhile, the Crusader's been digging entire mines with the Mountain Hammer, healing like he was a Wand of Lesser Vigor, and taking it like a man. I won't deny that the Paladin can do some serious damage compared to the Crusader, but that's because maneuvers get out-tempoed very early on.
But that isn't what the Tiers system is based on. The Paladin has ONE option during combat (Mount up and Charge), while the Crusader has several different actions to work with (White Raven is nuts). The Paladin's healing abilities do not compare to a Crusader's. And never mind Turn Undead (seriously, it rarely works unless the DM sends a horde).