I hate downtime too!
Some suggestions if you please:
Download a whole bunch of MP3s and Alt+K, makes time pass by faster
Social interaction, i cant alwase talk while kiting/tanking/croting, so downtime gives me time to chat, and more importantly group, if you have downtime while grouped, your mana/hp regen isnt the problem, its your choice of experiance.
MOST IMPORTANTLY
2 box, cant find a group, box a member, or if ones oom, sit and box the other while he/she has mana...