I'm never sure what you guys mean by clunky in this forum, everyone says everything is clunky in some way on these forums, but I will give you this; MNK has IMHO terrible hand to hand animations. I don't care that they're unrealistic, although a lot could be improved in terms of delivering impact. I mean they are straight up ugly, nonsensical, too slow, or the key poses are questionable.

Here are some examples that irk me:

Shadow of the Destroyer
https://i.imgur.com/W8UNSsa.png

Bad form, low angle on shadow of the destroyer. Aside from the fact that the monk does NOT commit on building up momentum and delivering a sick 720 kick at the end or something along those lines, he also lands with his back turned, one extra swirl for no reason.

Four Point Fury
https://i.imgur.com/APyPkle.png
Its follow up. Everything with four point fury is bad IMO. It's extremely slow, there's like a pause to the handstand, and then once again MNK gets up back turned to enemy. Why? Copying capoeira's wheel kicks or spinning on the back would've been way cooler.

Form Shift
https://i.imgur.com/AOwBVTG.png
Form shift, flailing arms around. Looks so bad.

Perfect Balance
https://i.imgur.com/MrzyanG.png
Perfect balance. Do I need to say anything? Bro.

Rising Phoenix
https://i.imgur.com/yaC8c8W.png
Rising Phoenix is obviously based on a Wushu butterfly kick, except the legs are once again low. Bad form, weak key pose, and another mandatory land and super weak twirl.

I think leaning into the fantasy of being a blitzing powerhouse is for the best, but man, when an uppercut lacks impact, RIP. I think their best animations are phatom rush, enlightenment, and demolish.

p.s: I dunno how to warp text with images so, links it is. I could probably post a million other things but I think this gets the point across.