He actually does something other then being the person that makes the comic relief

IDK, I haven't seen a single Ice Age movie in a long time

He always was a Megatherium, just a horribly shrunken one

^Mylodon actually(last I checked. Might've been Megalonyx)

Okay, but like actual Megatherium. Large one.

^I don't understand how it'd change. Maybe he doesn't do as many physics defying things?

Welcome back to the wiki, Eye Lad. Good to see you again btw

Since he has a much smaller size in the movies, certain places Mega Sid wouldn't even be able to enter, affecting the plot of the first film, and by extension the other films. Also things like him not being afraid of Smilodons including Diego as much or even being horribly scared of Frank and Carl given his size as compared to his much smaller form.

Would him being a Megatherium affect the art style or would he still have thumbs and a personified face?