Two silver linings -
iOS 8 probably won't be as radical of a departure as iOS7 was from 6. Having iOS7 run pretty smoothly on the iPad2 is already quite the achievement and should extend the life of it by another year at least. At the very least, I expect iOS8 to look like iOS7 from a UI perspective.
Apple generally makes pretty good decisions on excluding hardware from software updates (i.e. terrible user experience), so if iOS8 is indeed unavailable on the iPad2 it probably means it really isn't capable of running it. The iPad2 is astonishingly robust - I can still run almost everything I throw at it on iOS7 with little lag (yes, even Hearthstone).