I personally believe it's not easy to gank and kill Vladimirs especially when they know what they're doing; not spamming E near minions so that the lane is not shoved and resultantly harder for the enemy jungler to gank the opposing Vladimir.
His Q, once it has been ranked up to 3, is on a low enough cooldown that you can alternately cs with it, and his autoattacks, especially against passive laners, quite easily.
Lastly, I believe his overall kit has been noted to be undesirable (i.e. badly designed) not just by players but by Riot's champion designers themselves. He is planned to have a rework some time in the next two years; not because he's overtly OP, like pre-rework Sion or pre-reworked Master Yi, (though he can be once he's fed like every other champion) but because his kit is arguably the easiest to use out of all casters in the game as well as having very little counterplay. This results in a shitty and boring kit with the only fun part of his gameplay being watching the enemy team scatter like rats at the mere hint of him, and maybe his Sanguine Pool but then that gets boring after a number of games on him.
EDIT: Feedback given by the boards helps Riot discern the current concerns of players and (though seemingly very lightly according to many) use this feedback to balance the game. The boards are helpful in suading the balance teams.