You took out the on hit. Great, it was broken. But now there's no legitimate reason for garen to stack AS beyond TF unless he goes some full crit build.
His full crit build took a prett heavy hit since he now maxes out on only 30 resists with his Winstead of being able to reliably hit 50 each late game. Squishy builds will be quite a bit squishier.
Just looks like, at best, a power shit to make TF feel a little better at the expense of an already failing cleaver build (which SHOULD be his main playstyle build). At worst, it's actually a straight up nerf with garen losing considerable tanking ability at a time when tankiness already sucks balls.
The w is what allows garens to build heavy AD oriented builds right now. What makes you think that trashing it is going to free room for garen players to try to build AS/AD with new E changes.
Again, the on hit removal, justified. But you cant keep his w giganerfed with his e being much more in check now.