Blood Moon is a game mode for assassins specifically (and yet there are fighters and mages but that's a personal complaint that deserves another thread). I can feel why it sucks to be limited, but you can see it as an opportunity to learn new champions, or play champions you used to main (i.e. i played a lot of KZ when I was a jungle main, switched to top, stopped playing him).
It's really different from what we have currently because you can come back much more easily from an early stomp ; kills don't grant xp nor gold (unless you abuse Triumph, and even then it will give you ~300g per game, which is not that much when you're full build at 10 minutes).
Also, I've played a couple of games on PBE lately and the prefered keystone is Electrocute, you aren't punished by the bloody long cooldown lvl 1 since you gain xp really fast.
It might come down obvious that Blood Moon is one of my favorite game modes, but it's also there for only a weekend, and OFA is coming out Soon(tm). Just do like everyone else when it's Ascension, skip it and hope there's something new next weekend hehe