It seems like they left a ton of room for another sequel, seeing that the main antagonist of the universe is still alive and well at the end on Gateway 2. It’s one of the best IF games ever made. It would be especially relevant now because one of the main antagonists are a group of pro-AI terrorists who want to see humanity completely digitized. Also, with how much these games pushed the up the level of parsing technology in the early 1990s, (I think it kind of dropped off after that because of the pivot to point and click adventuring) I would really like to see what a team of the most talented and creative developers could do, if they were just focused on applying the most state of the art technology to making a great parser, as opposed to just fancy graphics.
I love Legend Entertainment’s adventure games, but I really have no hope of seeing any game of theirs getting picked up again. Certainly not the same team. And since so many of their games used IPs - Death Gate, Shannara, Gateway, Xanth, etc - the chances of seeing more of them are really slim. Even a fan sequel, because of this, has issues. I think it’s best to accept that the story can be simply left open-ended.
Seriously, Bob Bates created a true successor to Infocom. Sierra and Lucasarts are talked about a lot, with good reason, but Legend Entertainment is truly legendary.
But, I believe Bob Bates actually has a modern game out. Maybe someone could back me up? A post-.Legend, somewhat recent, game?
Yup, Thaumistry - it’s pretty fun!
Thanks! There you have it - that’s the closest you’ll get, probably. 
I think it’s TADS!
e: Yep, TADS