Leon's base attack knocks Yuri out of the air, no need for upgrade. Special moves knock Yuri out of the air i.e. slow attacks.
Yuri's laser is my favorite part about him, but it does horrible damage (it's either slow/pull or damage, can't have both). You'll notice if you play with me I can't kill anyone by myself, unless it's Voltair or another Yuri. Mines are definitely the thing to focus on when playing as Yuri, but I try my best to stray away from that norm.
Yuri always needs some of this to get the haters hating.