Yeah, I agree it's hard to find good medium for everyone, but here's my take.
I don't like ELO-system at all, I think simple 2 pts for win, -1 for loss would be better for worming community. I see it would boost overall and seasonal activity (average wormers wanna compete also with their 1-2 strong schemes) and most importantly, it makes it more fun. Every season would be fresh start with the new hype going on amongst players.
You can pick the scheme you actually WANT TO play, that's the main idea here, for a wormer to have fun while competing. In TUS singles it's not that big of a problem because you can find variety in Singles often and quite fast, but in clanners it gets annoying sometimes. You're chilling with your clanm8 and you guys would like to play Elite against some clan but after you finally find a clan, you notice that you get too low points for it, you're forced to pick Hysteria/WxW instead, which weren't the schemes you actually WANTED TO PLAY.

ELO-system forces you to become all-round if you want to be successfull, but so would this system also. People pick their strongest scheme so you're forced to become good at them also if you want to make + points.
Were a small community and we just want to have fun while having a competition between us, why restrict the amount of fun we can have when we just want to play the scheme(s) we'd like. There would be still tactical picks going on and all that jizz.