I would avoid CES (consumer electronics show) week. Room rates sky rocket and lots of places blackout those dates as far as comped rooms. And even if your comped room is honored, it is just such a busy time that tables will be more crowded than usual and limits higher (which probably wouldn't effect you). But the crowded conditions would.
Any other time of the month should be fine. There is a long Martin Luther King weekend in there and those 3 day weekends always draw big crowds from California.
Games downtown haven't changed much in the last year or so. There was a bit of a problem at some tables at the Spaniard over the summer, but that issue has resolved itself (at least for now). Can't think of anything else that has changed much recently as far as BJ downtown, but VP has deteriorates in the last year.