I tend to completely forget the non-classic era WB cartoons. The 60s and later versions of characters don't even come to mind. I know I've seen a Merlin the Magic Mouse cartoon, but all I remember is that the action took place on a stage – must've been really memorable! Another cartoon I remember seeing was Bunny and Clyde – I probably only remember that one cos it seemed in such delightful bad taste to base a whole cartoon around a 'cute' pun on the names of a couple of murderers! The modern takes on Looney Tunes haven't interested me much either so I don't have an opinion on Lola Bunny.
...So, for me, Sniffles is the worst Looney Tunes character that I can actually remember properly!