in any hotel I've stayed at in LV has been that there's no difference any day of the week, except that the casinos are a bit less crowded Mon-Wed.  Also, Wednesday seems to be a day where many of the hotel restaurants are closed.  I cannot speak directly about the Venetian, having never stayed there.

The bar scenes of late seem to be the same.  That is, in most hotels you'll find any number of girls working the bars every night.  I don't think busieness is as good as it used to be.

I personally enjoy LV on those days, and generally book Sunday to  Thursday trips.  All the indy providers are available, and the casinos, less crowded, are better, IMHO.

Good Luck!

F.