Just a curiosity question out there for you number crunchers: Does a troll's regeneration have any significant factor when it comes to effective time to live, or effective health?
Secondly is it possible or even worth anything to have enough spirit gear to pump this up significantly? One notices that taking a sample of spirit stats from various characters that spirit increases a character's health regen while not in combat by varying degrees (taking a quick sample of warriors level 60 - 70 they average aproximately 1.6 - 1.7 health per second while not in combat per point of spirit, it is unclear weather the troll's added 10% to this number is already factored in based upon the armory character sheets)
A troll tank by virtue of his/her racial ability maintains 10% of this regen while in combat - with a score of 56 on an armory sheet, giving a listed "additional" 34 health per second while not in combat, thus 3 health per second while in combat. Not a seemingly big number, especially compared with a tauren tank's extra health at level seventy.
It should be noted that the benefit of regeneration is much higher in the level 30 or below range - something I discovered while levelling a troll warrior, which makes that process in some of those spots significantly easier (i.e. better survivability and less downtime)