Might have the numbers a bit off, it's been a while since I haven't played much this past year until the last week, but from what I recall, like most stats in EQ2, Haste is on a diminishing returns curve. The more you have the less it helps. 100% weapon speed increase occurs at 125 haste, and haste hard caps at 200 haste (for a 125% speed increase). Get it to as close to 125% as you can or go over, but once you hit 125, it's preferable to make sure you get other stats like DPS up to their 100% mark (also at 125 IIRC).