Eh, there were a couple good ones in the mix. Quan Chi and Kenshi come to mind first obviously, they're really good characters. Fujin is right there on the cusp - I'd really like to see him come back and see what NRS do with him. Kung fu amplified with wind could be really cool IMO, you could have all these "wire-fu movie" type moves.
I'm pretty sure I'd love Bo Rai Cho if it weren't for the farts and vomit. Just have Sammo Hung do drunken style kung fu and you've got yourself a character. But the other stuff ruin him for me. (And I don't mean he can't be funny. His mirror match dialog in MKX ("You're drunk, go back to sleep") is funny, Johnny and Cassie Cage are funny, and I love them. But leave the farts out.)
Shujinko and the whole "old guy who has mastered the best martial arts techniques in all the world" angle has potential too, but he can't be a collection of copy-paste moves. He would've honed and perfected each move (in his opinion, at least), so while he could have Scorpion's spear, its utility would be different. (I think Takeda was a good example of this - Scorpion's influence is obvious, but the moves (spear, teleport) are still different.)
But a lot of the 3d era folk are really "meh". There's some cool visual designs, but that's about it. Having too many characters in a story also runs the risk of making the plot overly complicated, or some characters unnecessary (and thus, uninteresting). I think MKX had a good amount of characters, and MK11 looks to be that way as well. Sure, some are jobbers, but they fill that role in the narrative. You can't have a martial arts action story without some jobbers.