Anti-Mobility Buffs
My changes suggestions are anti-mobility buffs both directly to immobile champions and a larger universal change that indirectly effects mobile champions and indirectly helps immobile champions to equalize the disparity among these types of champions. My ideas are to first and foremost try to be ways to deal with mobility creeping within the game (the success story is the game feels less mobile with my ideas, so the ideas will most likely feeling majour nerfs to mobile champions and bring back the immobile champions).
Unless specifically stated Flash being affected then Flash will be an exclusive to when I say instant teleports, despite the spell being an instant teleport (instant teleports that require channels like Fiddle ult or Lissandra claw will be considered instant teleports).
Ashe: Frost Shot (Q): Must be toggled ON; but when Ashe's basic attack exceeds 1100 units of her initial location then the slow is increased to 99% for 2 seconds.
Anivia: Crystaliize (W): When a target dashes, jumps, or instantly teleports pass the ice wall then the unit is slowed by 99% for 3 seconds, applies as chilling slow so Frostbite (E) may critically strike.
Cho'Gath: Vorpal Spikes (E): Must be toggled ON; but the spikes mark struck enemy champions for 2 seconds that when the champion uses a dash, jump, or instant teleport then they get snared in place for 1.25 seconds afterwards.
Volibear: Rolling Thunder (Q): When an enemy champion dashes, jumps, or instantly teleports then the movement speed bonus increases to 60/70/80/90/100% [this is double the normal movement speed] towards that enemy champion.
Veigar: Event Horizon (E): If a target dashes, jumps, and now additionally instantly teleports pass both the delay circle and stun wall then that target will be stunned. This is so that mobile champions are equal to immobile champions, so that they can try to walk out of the circle before the stun walls appear, but they cannot use their dashes, jumps, or instant teleports otherwise they get stunned anyways, this is to create fair gameplay for everyone and make Veigar's trap more threatening by instantly having an anti-mobile trap and not just a trap that prevents immobile champions from escaping- also additionally instant teleports now be affected by Event Horizon instead of just dashes and jumps.
Skarner: Impale (R): Now extends its range if the target used a dash, jump, or instant teleport if the spell was already being cast.
Udyr: Bear Stance (E): Movement speed decreased to 5/7.5/10/12.5/15% from 15/20/25/30/35%; movement speed increases to 20/30/40/50/60% when moving towards enemy champions. Udyr is a problematic champions with being too safe with Bear Stance's movement speed but also very kite able because the movement speed is not good enough, this makes it so that Udyr can be caught out making him less mobile but giving him a stronger gap closer to be relevant in fights instead of being this kited sponge.
Big and Large Scale Universal Change for Summoner's Rift: When a champion uses a dash, jump, instant teleport, or Flash pass non-champion impassable terrain then that section(s) of terrain will glow either red or blue for the next 5 seconds causing the opposing team to freely walk through that terrain (the colour terrain is the team's colour that is eligible to pass through the terrain). This change is so that there is not this HUGE discrepancy between mobile and immobile champions (and perhaps less Flash usage with this change, perhaps we could see two summoner spells). The change is so that when a team picks their leblanc, corki, ezreal, lee sin, kassadin, etc you playing cho gath, ashe, anivia, etc can chase these super mobile champions granting their terrain escapes to no longer be escapes and have an equal playing field between the Ashes and Corkies.
Comments and concerns are welcomed, hope you appreciate the ideas to aid in trying to deal with mobility, and have a nice day! ~ Stacona