As it stands, in order to practice a killer, you need to shanghai a friend to a custom game, or brute force your way to learn through public matches.

Let us take AI survivors into custom games, with programmable options like, "stands still" "always flees" or "aggressive". Stuff like that. This is mainly so you can practice such abilities as the Huntress' hatchets, to learn arcs and such, or Trickster's daggers, to see what tiny holes he can actually toss blades through.

Failing that, let killers or survivors go into a custom game alone, so we can explore maps at our leisure. You rarely get to actually explore a map in public matches, so focused on doing gens and surviving.