Instead of debating the merits of whether the monk should have certain thief skills, what if instead we flipped the script on the thief and gave it some sort of unarmed fighting option -- as in, a pretty good fit in a back alley fight club or whatnot. The thief has plenty of abilities that would scratch that skill monkey itch, and if one doesn't want to, one doesn't have to play it like a straight-up criminal.
What I'm saying is, I'm going to mash up the time-honored tradition of 'fixing' the thief with an unarmed combat approach totally ripped off from someone's take on the monk.
I'm thinking Moses from Ms. Scarlet (and the Duke, until last season). A character that would fit in most any fantasy-ish setting without having to explain how said character obtained all these clearly mystical abilities. It's probably already been done, so I reckon I should poke around the rpg blog-o-sphere before I get too far into the weeds.