Mobs on leads don't get stuck on one-block jumps

I think the biggest problem with leads is they are constantly breaking when you try to get a mob to jump up one block higher than they currently are. You make the jump immediately, and keep on pulling, but the mob gets stuck for a couple of seconds, and suddenly you're too far away and the lead's broken. (This especially ruins the functionality of llamas, whose whole purpose is to be led around. They're such a cool mob, but they can't really be used for their intended purpose!)

Making leads unbreakable might be too overpowered, so maybe instead a good fix would be to change a leashed mob's movement behavior? Find a way to make them more proactive in following the player up a gentle slope, that they don't pause a couple of seconds before finally 'figuring it out'?

Thanks! :-)