can you just stop trying to change celerity?
seriously, the rune is fine as it is. stop trying to fix what isnt broken and focus on what is.
unless your goal is to break 
Celerity (S3)
Movement speed lowered from 3% to 1.5% Adaptive AD increased from 4.8% to 9.6% Adaptive AP increased from 8% to 16%
referencing the current pbe changes
this is just generally going to make the rune more champion specific, than to the players preference. if this goes through, its going to be more valuable on champions with inbuilt high movement speed bonuses, and less for everyone else.
wasnt the entire goal of the rune system to allow people chose chose runes according to their playstile and not the champion theyre playing?
cuz its gonna be crazy ap