[suggestion] Teleport under homeguard = cdr instead of speed

Could we negate the speed boost and instead give a lower cooldown to the teleport spell when used after 20 minutes ?

I'm affraid that homeguard and teleport will cause just a few champions to be extremely strong with it. Champions like hecarim or with short range potent stun like jax, taric, rammus.. while other players trying to use teleport as a defensive tool will be punished now. What is the point of having teleport when you can back with a free homeguard ?