I recently got my second toon to Fiddy (Last Prime, Guns/Dev Blaster), and have come to a decision...
This is not as much fun the second time around.
Yeah, it still IS fun, and there's lots of content I didn't do the first time around, but there's just not as much spark, for me.
I'll probably pop in and out from time to time, but I won't be playing quite as much. Might wait on Champions Online and try that one out...