Bottled Wishes is better. You want as much burst as possible on demand and with a very short cd. You are most likely gonna be doing the tendons in 3 goes (unless you have insane class stacking, korean style). The MWC doesn't cut it because the cd is too long (other 2 min cds arn't up every tendon burst). With a 90 sec cd however its always gonna be up. (you also dont want to wait with getting the tendon up because you will get over run by the blood). This is the same reason why the encounter heavily favours mages and rogues- on demand burst with a very short cd. So bottled wishes is up every time you burst the tendons whereas mwc is not which makes bottled wishes massively better as its up on double the number of tendon phases.