The proper term is “rhetorician”. And calling myself a rhetorician would be very misleading. I would never even pretend to be one. I can write well, but I’m not that good.
But there is no such term as “rhetorican”, as far as I can tell, any more than there is a word spelled “physican” or “aesthetican” (which would rhyme with Mexican, I guess). But I wanted something distinctive for the blog’s name. A Rhetorican might be a citizen of Rhetorica. Who knows?
It’s really of no importance, except that I would hate to promote the misspelling of such a cool word as “rhetorician”.