I really think that "should have" is going to be replaced by "should of". It already is in most actual usage, and it's only "language snobs" (like me) who care that it shouldn't be used like that.
I have the same feeling about "lose", which is increasingly spelled "loose". It annoys the living crap out of me, but in fairness English is whatever people say it is, and if people want to say it's "loose" then so be it.
I've already seen "moorish" succumb - from meaning (more or less) "spicy" to meaning "something I'd like to have more of". Which to be fair we don't have a word for, while we have plenty for "spicy" so it seems like a fair trade.