Speed buffs are too overpowered, since you don't stop when using defences now it is waaaay too easy to just run away from someone. I agree that people should have a opportunity to run away but it shouldn't be THAT easy. You can literally take 3 speedbuffs in like 10 seconds and run away so far away that you can just hearth back.
My idea : make the buff not stackable so picking up another speedbuff would just make it disappear not make you faster AND set a cooldown that you can only pick up 1 speedbuff per minute (while on cooldown you can pick up speedbuffs but that will only make them disappear)