Why is no one abusing storm razor on garen

I tried it out and it seems so busted, I 1 shot squishies almost instantly, though I would only rush it if I'm in a poke lane, because it's build components are too weak to make it a good first item into champions like darius, I would build it 2nd after triforce or black cleaver in those lanes.

Storm razor gives everything garen wants, a slow on his q, crit damage on his e, more spins with attack speed, and more damage.

If u are doubting me, just try it one game, and u'll see what im talking about. Instant death to squishies.