To be fair spending 1 dollar to get a 3 star hero that can and will be used in events (We all know there will be more ubisoft events in the future) is a good deal.
The previous rayman event was pretty poor.. but you would be able to get like 20 awakening items and some blue/purple crap, it could have been worse.. Add to that the rewards from these events and I personally feel that it was a dollar well spend. You got a pretty decent amount of value for just 1 buck.
With regards of arena events... I want less of them... it is very hard to keep rank and try and get the events done without spending any diamonds on extra attempts. But I prefer these specific hero events over the random crappy arena events where I cant see who my opponent is or where fireworks determine who would get more boosts -_-.