The idea is good although it seems that the hp pool doesn't raise beside more constitution. The main problem is that certain classes won't get a group or atleast you need different spec from your usual rvr spec. Respeccing is expensive for just one run and twinking is not funny for everyone. I would prefer that the bonuses you can achieve are account wide like the exp bonus. Then it really woudn't matter to help with a twink which you won't play otherwise.