Very Few assassins have point and click burst maybe?
Akali(rework comming soon), Talon(though he still has 2 skillshots but they are hard to avoid, he's getting nerfed though.), Nocturn(requires lvl 6 unless your already inting.) Kha'Zix okay you can have that one. Leblanc? Debatable i guess, Shaco? He got nerfed out of burst a long time ago. Rengar? A bit too easy to shut down but i mean yeah, mostly point and click i agree.
So 6, six out of the 16 total assassins have point and click burst combo's.
The rest of them are riddled with Skill-shots and most don't have any CC either, or if they do they pay a price for it, or it's very hard to land.
Ekko: Lowest burst of any Assassin, he only has 2 abilities that burst and his CC ability is arguably the hardest to land in the game but it's his only reliable way to kill someone in under 3 seconds.
Evelynn: Extremely high burst, no mobility, a charm that takes 2.5 seconds to arm and tells you where she's at, she's basically screaming at you "Get the hell out." but people don't listen.
Zed: Point and Click R with a delayed burst that requires you to hit your other abilities first, if he's fed sure he can jump out of a bush and double Q+AA you but i mean, that's true for literally everyone in the game.
Fizz: Okay Point and Click Q that does basically no damage since you have to max your E or die, hard to land skillshot ultimate that accounts for nearly 40% of your total damage, requires level 6 to one shot.
Katarina: I don't think i have to explain this but katarina is fucking hard to play, her E might be point and click but the vast majority of her damage comes from her Passive procs, which you have to play around in order to play her properly at all.
Kayn: He's probably one of the easiest assassins to play but when going Assassin kayn if you miss your W, good luck killing anyone because that's where most of your burst comes from, your R is a point and click delayed extra damage ability(like Zed) but your not one shotting someone with it.
Pyke: This %%%%%'s a support.
Ahri: You NEED to land your E, if you don't you do legit 0 damage, unless your fed but again that's the same for any champion.
Kassadin: Direct counter to mages and AP assassins in the mid-lane, takes a long time to get to where he needs to be to burst someone and more often than not can't do it at all until he gets to that point.
Also let me point something out, these are legit ALL OF THE ASSASSINS IN THE GAME, that are actually building like assassins, riot might list Riven and Fiora as assassins but they DO NOT build like them and don't have the burst usually either. Do you know how many ASSASSINS build duskblade? 8 of them, do you know how many are AP Assassins? 8 of them, that's right, when your discussing ASSASSINS don't lump them all together as Duskblade user's, because half of them can't even build the item and get anything out of it.