Correct me if I'm wrong, but wasn't it the Rune Chopper DRK builds that lead to haste caps? I don't remember any caps before that.

Rune chopper was cheap and available to just about everyone, and the gear builds were very similar. The difference was, K club maxed out at about 270ish a hit (I was Mithra with 8/8 HP merits so HP wasn't as high as Galka) while Rune chopper could easily top 400+ per hit, making it much more powerful than K club zerg. Not to mention the extra haste you got just from having Rune Chopper equipped.

Note: I quit when the cap was still 75 so the above info is definitely not still true.