At the moment we don't have every tm in the tmshop, which could be very annoying, since those moves also aren't provided in the move tutor.
So maybe its a idea to add the missing tms to the tmshop
It's a decent suggestion but I don't see the point because it would essentially make wandering tmshops useless. Ideally you'd want people to use the features in the game otherwise there's not really a point in having them if you know what I mean.