Any skull that requires you to do the grenade jump should be removed from present location and put in a location on the ground where people like me who can’t do the stupid grenade jump can get the achievement
The only one that I found pretty hard to do is the ‘silent cartographer’ one. The others are really simple, once you know where they are ( and, in 2018, I can search on three different mobile phones/tablets at the same time to find them ).
Anyway, skulls are not something you walk in randomly, they are hard to find and, sometimes, harder to get. It is great that these skulls are sometimes place outside the limits of the map ( a little bit, not like dolls in h2a ). Doing a granade jump is like the first thing someone apprehend playing the campaign to get skulls and easter eggs.
You say that you want easier skulls because you want the achivement, and I can’t wait to see what you will say about easter eggs positions. In 2018 is really easy to find guides on the internet that explains everything ( each position of terminals, skulls, easter eggs ), without a hard way to get them it would be actually too easy.
As i said, something I find a bit excessive are the h2a dolls: particularly the delta halo and the great journey ones, which are places outside the map.