Originally Posted by
Azyoulike
You're already at haste cap so all you'll really get is the faster regrowth. Nourish will hit slightly faster but then you'll be left waiting before you can cast the next, so there's no benefit in PvE. Rejuv will tick faster which means it will fall off faster so you won't be able to cover as many people - or (in 10 man) have as many spare GCDs for casting those 1sec nourishes.
Going over the haste cap has some small benefit if you might only have 1 of the two haste buffs in your raid, or if you're aiming to drop substantial haste later (ie. when switching a haste weapon for Trauma).
Otherwise it's just giving you more time listening to the immortal line 'I can't do that yet'.