Makes me want to run a game following the latter half of the trilogy. Like, what if some elementals figured out how to summon humans? Or what if doing a summon to bind an entity to an object went really wrong.

It's intended to be handwriting friendly as a printed sheet, hence the large space.
But yeah, a planescape-like setting would work really well. It is intended to work, with only minor adjustments, for basically any setting though.

It is and it isn't. Equipment isn't central and a variety of different types of equipment could be used to solve the same problem. Actions make up the bulk of choice making to form a well balanced party.

This is my current big TTRPG project.
The longer form text about it I put on my Tumblr blog (because it works well for long form posting). Keeping track of shorter form updates here on bsky.

This post is probably most comprehensive dev blog currently www.tumblr.com/dungeonmalco...

I feel like most systems either use a dice pool, percentile, or run on d6s is what I was trying to get at. Seems like only the big box games run a d20 system with variable DCs.

Absolutely. Cards can be incredibly useful. Clunkiness does not negate usefulness. I'm also a big fan of analogue. Digital is typically a one page at a time limit, analogue let's you see lots of things at the same time. That's the benefit of the clunkiness. Two sides the same coin.

Look, this is getting into interrogation territory. And I have no obligation to endure that with this character limit (or at all really) If you want an actual discussion, I run a tumblr blog where I covered all this over a year ago.