This is absurd. Re-evaluate their path? Skillpoints are permanently assigned. If you're okay with wasting a bunch of skill points, then okay. But I'm not. The game's systems should function together in a coherent and sensible way. Which means if I put points into pyro, then I should be able to buy the fire spells for my character that I want/need. Not being able to do so (which sometimes happens as a result of the excessive vendor randomness) means the system is broken in some fashion.
Just because a vendor doesn't happen to have the skills you want, doesn't mean the skills aren't available in game. You just don't get the skill exactly when you want it. It adds some variety to the game even if you were to do a new run with exactly the same char build.
I think it adds to the enjoyment of the game. And I don't think that is absurd.