What if Garen could not be slowed past a fixed amount while Q...

Garen has a base movement speed of 340. When he activate Q, Garen breaks free of all slows affecting him and gains 30% movement speed for 1.5/2/2.5/3/3.5 seconds. His next basic attack within 4.5 seconds deals ...

What if while the speed boost was activated, Garen could not be slowed past a fixed amount. Say his base movement speed. However, any additional movement speed buffs would interact as if he had the slower movement speed. This includes things like the passive of Dead Man's Plate etc.

Another version would be that Garen cannot be slowed beyond 330/332/335/337/340 movement speed while the speed boost portion of his Q is activated.

Ideally, this would be put onto his Q. However, if deemed too strong in the early game, it can be put on E. Currently, Garen maxes Q over E for the bonus movement speed and upfront damage on Q. If this change is put onto E, and if Garen is maxing Q, then he will have the longer duration of the movement speed. However, his movement speed floor would be at 330 instead of closer to 340. This change allows Garen to decide on the upfront damage and speed boost duration of Q or how much he is willing to be slowed down to.

Now to look at this buff as both the enemy and as Garen.

As Garen, you still want to bait their slow before you use your Q. Often times, you use Ghostblade active and bait the slow, and then you proceed to use Q. So it is not that effective in that sense. However, if you do use your Q, and then get slowed, you will still be left with ideally your base movement speed.

As the enemy, Garen can still be kited with a movement speed of 340. Think about a Garen with no boots and his Q down. Very easy to kite still.