Since patch 3.2, Seal of Wisdom has become even more of a staple than it previously was. Why?
Judgements:
Patch 3.2.0 (2009-08-04): Some of these attacks were considered ranged and some melee. They are all now considered melee attacks that can't be dodged, parried or blocked.
This is huge, whether you realize it or not, because Seal of Wisdom procs from melee attacks. This means your Judgements have a chance to proc Seal of Wisdom's 4% MAX MANA return (not base).
Now the thing even less people realize is that the chance for Seal of Wisdom to proc from Judgement of Light/Wisdom/Justice is a PPM (Proc Per Minute) effect. This means that all weapons are equalized for proccing Seal of Wisdom from Judgements, right? WRONG.
A slower weapon has a greater chance of proccing a Seal of Wisdom from a Judgement, up to nearly 100% at a 4.00 speed. Assuming the standard 15 PPM for Seal of Wisdom, we get the following:
1.5 speed: 37.5%
Notable weapons: Heartcrusher/Heartsmasher (haste/crit, ToC10 Tribute, ilvl 245)
1.6 speed: 40.0%
Notable weapons: All PvP 1-handed maces, Firesoul (haste/hit, FL10, ilvl 219), and Splintered Icecrown Parapet (haste/crit, Marywn N, ilvl 219)
1.8 speed: 45.0%.
Notable weapons: Nearly all caster weapons in the game are 1.8 speed.
2.1 speed: 52.5%.
Notable weapons: Quel'Delar, Lens of the Mind (haste/crit, ICC5 quest, ilvl 251)
2.2 speed: 55.0%.
Notable weapons: Lockjaw and Lockjaw Heroic (haste/mp5, Rotface10/10HM, ilvl 251/264), Valius, Gavel of the Lightbringer (crit/mp5, Lich King 10, ilvl 258), and Seethe (haste/hit, Devourer of Souls H, ilvl 232)
2.3 speed: 57.5%.
Notable weapons: Warmace of Unrequited Love (mp5, H Nexus, ilvl 200)
2.4 speed: 60.0%.
Notable weapons: Glinting Azuresong Mageblade/Polished Azuresong Mageblade (crit/hit, Onyxia10/25, ilvl 232/245)
2.5 speed: 62.5%.
Notable weapons: Titansteel Guardian (crit, no int, crafted, ilvl 200)
There are no epic lvl 80 weapons with speeds other than those listed in the list here.
Basically, every increase in weapon speed by 0.1 gives you a 2.5% chance increase in getting Seal of Wisdom to proc from Judgements.
Okay, dcemuser, I see how weapon speed can increase your mana return through SoW/Judgements, but how can I calculate this?
It's so easy a caveman could do it:
Mana return through SoW from Judging = [(Weapon speed * 0.25 * 0.04 * MAXIMUM mana pool)/(Frequency between judging)] * chance to hit (usually 96% since they are now considered melee attacks)
To convert this number to MP5, just multiply by 5.
For example, let's pretend I'm rocking Lockjaw (a 2.2), with 40k mana (fairly standard), and I judge... every 50 seconds, because I don't want to risk losing out on JotP if it misses. Then my mana return is 84.48 mp5. Lets compare this to a 1.8 weapon. Imagine there was a weapon equal to Lockjaw in every way, except that it had a 1.8 speed. In that case, the return is 69.12 mp5.
Big deal you say, it's only equivalent to one and a half mp5 gems, you say. Well, when we change the frequency, things change a lot more.
Alright, now, let's pretend I'm judging every 20 seconds, to maintain JoL, or JoW, or even Heart of the Crusader in some 10-man group with weird buff synergy.
With a 2.2 speeder, the mana return will be 211.2 mp5. That is equivalent to some of the best mp5 trinkets in the game. Now, with a 1.8 weapon it's only 172.8 mp5, which is a fairly massive difference.
Okay, I believe I've made my point - don't ignore the weapon speed on weapons because a lot of the time it ends up being more valuable than the static mp5 or int (rarely) on the weapon.
Edit: Worked on the examples a bit, going to throw up some real comparisons and better formatting later. Have things to do now.