The Sociopath: According to Bugs anyways. He does have the lack of empathy part very much down (though subjected to Depending on the Writer), but he does have traits sociopaths clinically lack, like feelings of shame, which are consistent with him being a narcissist instead. On the other hand, he does have a short temper, is impatient, shifts blame and is stupid, traits more in line with real sociopaths than the fictional evil masterminds and manipulators.
Took a Level in Dumbass: In the original shorts - at least, in his most iconic personalities - he was fairly intelligent and clever, but occasionally gullible and was often defeated due to his greed and selfishness. Here, he's a lazy idiot who can't do anything right and fails to answer even the simplest trivia questions correctly.
Took a Level in Kindness: He's nicer than in the original shorts. Partially justified because he's no longer allowed to use his trademark pistols, so he can't intimidate and bully people as easily as before.
Demoted to Extra: In this adaptation, Elmer mostly serves as the local news reporter. With the exception of a brief interaction with Daffy in "Year of the Duck", he has yet to actually interact with the main cast.
For the Evulz: In "Customer Service", Cecil annoys clients of his cable company for the sheer sake of annoying them.
Jerkass: Probably the biggest if not only jerkass in this adaptation.
Manipulative Bastard: In "The Shell Game", Cecil manipulates Bugs and later Porky into giving him money in order to fix his shell which was "accidentally" broken by them in two completely separate car accidents that he himself set up.
Took a Level in Jerkass: In the original shorts in which Cecil starred alongside and against Bugs, he was generally a foil to Bugs. In this adaptation, he is given an extremely jerkass personality reminiscent of the various antagonists that justifiably deserve Bugs' Karmic Trickster antics.
Turtle Power: Though unusual in being unambiguously malevolent.