I just want to be entertained. A non-quippy Ultron in hindsight would have been boring me to tears. No one likes shallow, 100% evil, one-dimensional bad guys. Hell Skeletor was quipping back in the day and the dude is a hooded skeleton that wanted to murderate He-Man. Joker, classic baddie but would be dry as a bone in Death Valley if he didn't bring twisted or quippy humor to the table. Leave the Terminator style bad guys to their own movies because that's about the only place they worked.
X-Men baddies without quips/humor could end up being...uhhh, Brood? I just imagine these people saying 'X-Men needs to be serious!' aren't thinking of things like Iceman, Mojo, Rogue and Gambit flirting etc. It's aggravating to hear.