Serqet had her niche in Season 2. While she's still strong and underrated (and my main), I'd like to tweak two things about her.
Regarding "Ambush", it bothers me that, if you cancel the stealth without leaping, it still goes on full cooldown, even though you only used half of the ability. In my opinion it would've been better if the cooldown was halved after canceling the ability.
Secondly, "Cobra's Kiss" makes enemies attack their nearby allies but only deal the same amount of damage to them like "Cobra's Kiss" does. Why don't they deal the real damage of their basic attacks? Maybe it's too dangerous if you get hit by your ADC with crits. But this would require more carefulness when being around Serqet.