True, the problem is, mainstream Christianity is mainstream. It is traditionalist to the core, shallow, and all to often obsessed with control.
I'm concerned though that any form of non-mainstream Christianity has no rigid system (of values, rituals, effective spiritual practices). Someone going for Sigils probably belongs to a protestant branch or got bored enough within the traditional branch, none of which pleases me - because there is quite a lot of confusion and division between the denominations of Christianity already. I'd rather go for something new entirely, like Luciferianism. Or return to local pagan traditions.
Go ahead.