Malchor's Fingertips Vista, awful design.
SPOILER ALERT
There is an alternative route to that vista. I discovered it after failing the jumps just like you did. Basically you 1st jump to the cliffs on the left side of the “finger” shaped rock where the vista is. Then you jump from that cliff onto that rock and the rest is easy. I did it with several characters and if you come to my server, Blacktide, I can show you how to do that vista the easy way.
Deniara
I don’t recall having any issue with it, personally the in the south east of Lion’s Arch is worse having to climb up what seems like a vertical wall and not being able to see anything since there’s shrubs all up the path (it’s not difficult but you can’t really see anything to even have the slightest clue if you’re going the right way)