Another modable game, even in the multiplayer version, is Torchlight 2. Characters get a pet on that one that will carry stuff for them, and also take stuff to the market to sell and go shopping and bring stuff back. One of the critters is a ferret. No, I don't play it. lol Can't do animated games. They hurt my eyes.
It came with a game mod tool kit, and really (Bioware knew this) the longevity and best stuff came from the modding. Whereas some current games hold "art" or fan competitions, they held "who can make the best mod for NWN" competitions :3
(You are correct, most current games do restrict or altogether forbid modding...which is why they lose a decent number of the PC community)
It is on the 101 games you need to play list...
It is still my favorite game...it had a massive modification community (out of ~60000 people, produced 10000 modifications and game modules (single player stories/gameworlds)