Murray - Constant swearing, mug.
Rafa - Rosol bump, badeye / glaring at opponents, occasional swearing in Spanish, time wasting, gamesmanship
Nole - time wasting, gamesmanship
Federer - rare swearing USO'09 and AO'13, arrogance
Who's the worst?
The one you hate most.
When was the last time you saw Nole play? You haven't been timing him for at least 6 months: he's one of the fastest players now.
Gamesmanship? When was the last time? I saw Wawrinka geting his legs massaged 5 or 6 times during his match against Nole... But nobody seems too bothered about that fact, then again, I'm sure the tennis community wouldn't have been bothered if Nole was the one who had done it.
You'll have to find something new to criticise about Nole. Those two do not apply anymore.