I'm actually trying to think of some champions they released in the past 2 or 3 years that don't have a stupid mobility spell that only succeeds in making them frustrating and annoying to play against.
No mobility, but has his own share of frustrating mechanics. (Like the stupidly high damage on his Devour)
Technically no hard mobility, but her ult still makes her invulnerable, deals damage, and sets up a free 6-Feather E nuke. Oh and she can still move and Flash/Heal as normal during it.
Once again, no "hard mobility", but has his Magical Journey, which is a pretty damn good escape for an "immobile" champ.
Another one that lacks "hard mobility", but still has a near-permanent Ghost, a snare, and an irritating slow, so he'll still kite the hell out of you.
The only one in recent memory that lacks any true mobility garbage, IMO. His E is so unreliable and easily broken that it doesn't really do much except get him into lane faster. Still, ignoring terrain is pretty crazy.
No real hard mobility, but ult is still a really big movespeed buff.
On the other hand, I could spend a half-hour naming off champions with a piece of strong mobility, usually unnecessary, somewhere in their kit.
W is basically a Flash with Yasuo Tornado attached. E range is low enough (without Xayah) to be forgiven. R is just a stupidly high movement speed buff with a mass Ahri E.
Special shoutouts because of that damnable ult. Think you caught her out of position? Nope! She just ulted and did like 700+ damage because of the free Feathers her ult inexplicably sets up for her E.
E can go straight to Hell where it belongs. R shows that Riot has a major hard-on for invulnerability-granting dashes, especially annoying since it's a far superior Jarvan ult.
Q is one of the hardest engages in the game. Snare one poor sucker and 6 champions (5 + Daisy) are gonna make sure that he's not getting up.
I can forgive this one since his entire kit forces him to go all-in, so he needs a little something to stay stuck on his target.
Her W has a low enough cooldown as it is with all the CDR in the game. Does she really need her ult to reduce it even further to a BASE of 2s? (2s * 0.6, or 60% of the base cooldown to account for 40% CDR, = 1.2s CD if she ulted)
Somewhat forgivable since her Q is rather useless on its own and messes with autoattack timers in a fierce way. Still a LOT of dashing to deal with.
I still have PTSD from Ekko in his prime. I can't even begin to describe the hate he inspires in me. Moving on before I punch someone.
Dumpstered, retooled, gutted, and dumpstered again because of how much presence her Tunnels + R gave. Definitely has too much mobility.
The only champion in the entire game that has a 0.9 AD ratio on autoattacks. Gutted over and over because of how stupidly busted her passive was. People warned Riot, and Riot didn't listen. Kalista paid the ultimate price for it.
Shurima Shuffle. Enough said.
Actually is necessary since his kit pretty much revolves around Bounce-Hopping off a minion into the fray. Annoying? Yes, but needed.
I could keep going on, but I think the OP's point rings painfully true. This doesn't even account for reworks, which would add
and
to the "annoying mobility" list.