The duration of spells are based on caster levels however the duration of action boosts are a constant 20 seconds. i would like to see action boosts be class level based. starting at 20 seconds and adding 2 seconds per class level. this would mean a level 20 rogue would get 60 seconds of rogue haste boost and a 18 ranger/2 rogue could get 24 seconds of rogue haste boost and 56 seconds of ranger sprint boost. This dose not mean it would extend the durations of abilitys that use different action boosts like power surge.