Mobility Creep'd
So obviously League of Legends is very mobility creeped with the amount of dashes, jumps, and instant teleports in the game; but I believe we can add anti-mobility to spells on non-mobility champions and make certain effects once again strong even against dashes and jumps like slows which fell off in favour tremendously because of all the dashes and jumps (instant teleports are even on a worse scale; no one likes playing against the likes of Kassadin, Leblanc, Zed, Katarina, Ezreal, etc. who all have instant teleport, with Leblanc being initiatially dash that becomes an instant teleport on second cast).
I believe instant teleports need a majour rework similar to how the stealth needed a majour rework which happened all the way back in season 1 same with dodge removal which Jax kept but as a active moment rather than a luck passive; but besides instant teleports we will discuss more on dashes and jumps this post!
Some individual quality of life buffs for champions would be:
Anivia's Crystallize (W) the ice wall will stop Dashes/Jumps if they attempt to go over the wall; similar to Veigar's Event Horizon. This will bring Anivia back into play without granting her any direct power within her kit; just bring power back to the wall like how it used to be back in season 1 and 2; despite this being a buff it does not grant Anivia actual power, but brings her back into the meta.
Malzahar's and Skarner's ultimates will take priority over dash/jump spells. These are ultimates and a basic spell should not take priority over an ultimate; should be common sense here.
Skarner's Fracture (E) will reduce the effectiveness of dashes/jumps by the same slow %.
Zyra's ultimate gains a new anti-mobility effect of reducing dashes/jumps distance by 50% if they were used within her ultimate before it knocks them up; but the thorns will also stop the movement of the dash/jump if the dash/jump would have fully exited the thorns meaning you have to walk out of her ultimate just like an immobile champion has to or Flash out of it.
Ashe's Frost Shot (Q) the chilling slow will reduce the effectiveness of dashes/jumps by the same % as the slow strength [slow strength goes up by rank]; so this helps Ashe greatly in a mobile world especially the % value really lowers the strength of more majour dashes and jumps by a lot more than short range dashes like Vayne's Tumble.
Evelynn's damaging spells mark struck champions for 1.5 seconds and if a marked champion dashes or jumps then Dark Frenzy's (W) cooldown refreshes.
Fiddlestick's Terrify (Q) will cause Fiddlesticks to move 50% faster towards Feared champions (mainly only useful if a target dashes/jumps/instant teleports at the same time as Terrify was used; other scenarios this is not entirely useful since the target is already CC'd but it grants a way for Fiddlesticks to deal with mobility champions in certain conditions)
Jinx's Flame Chompers! (E) once already FULLY set up if a champion tries to dashes or jump over them then the chompers will stop and snare the champion in place (there is roughly a 0.75 second set up delay remember).
Mordekaiser's Mace of Spades (Q) becomes a placement skill shot with a range of 850 units; AoE ~250 units; damage is the same; isolated damage is the same. (Remember this skill shot will travel so getting closer means an easier to land skill shot; but a skill shot instead of a modified basic attack means mordekaiser can get off his damage as an immobile melee mage in a mobile world without changing the master of metal at all.)
Twitch's Venom Cask (W) will reduce the effective of dashes/jumps by the same % as the slow strength.
These are the champions that can get anti-mobile buffs without affecting their power levels, but at the same time helps them into the mobile meta while staying as immobile champions as they should be (even though I understand some of these champions have speed boosts). Other champions either needs rework / gameplay updates or are very strong currently and don't need anti-mobility buffs; even though these champions I listed may be strong there is still the immobile and mobile discrepancy and these buffs will helps the champions in a mobile world. Even though this is not an end all solution these changes will help reduce mobile creeping; there is still direct nerfs needed for the really mobile dominant champions like Zed, Leblanc, Katarina, Kassadin, Nidalee, Irelia, etc. but a start is a start; and you need to start somewhere.