There are only 7 champions in the game that have a silence 
.
You can remove because soraka's is only in effect while you are standing in the circle, which is completely avoidable. Kass and blitz are only slight interruptions, meaning they basically just stop channeled abilities. So now you've got 4 champs with an actual silence.
's W starts at 1.6 seconds, is AOE, and has range. So already it's better than Garen's Q. It then scales up to 2 seconds in duration.
E is 1.25 seconds, can hit 5 targets, is point and click, and again, ranged (You can see where im going with the whole range thing)
Q is 1 second, aoe, and ranged. It scales up to 2 seconds.
If you want to whine about silence durations, you need to whine about all three of these first. Garen has very telegraphed abilities and you always know what he's going to do when he's about to do it. Most melee top laners do pretty well against Garen, and aren't affected that much by the silence.
My thoughts on this are that you need to learn how to play against Garen. He's the easiest champ in the game for a reason.
Does he need nerfed? No
Does he need buffed? Maybe
Does he need a kit rework? Definitely
