OSR Hybrid TSR era clone, does it exist?

[Jack Daniel]

I'm quite the opposite. I don't see the point in using an OSR system unless it eliminates descending armor class by default. It's the line between an old school reprint and an old school renaissance. A return to the old school gameplay style and not just mimicking the mechanics and hoping the result is the same. Bringing back the most cumbersome attack roll ever in order to enjoy older gameplay styles is cutting off your nose to spite your face. It'd be like bringing back tank controls just because you want to play a remake of Tomb Raider or Resident Evil.

Descending AC is the least cumbersome method—if you have discernment enough to pair it with an ascending attack bonus and roll under.

Guy with no armor (AC 10) being attacked by a fighter with +5 to hit? Chance of a hit is 15-in-20.
Guy with full plate (AC 3) being attacked by that same fighter with +5? Chance to hit him is 8-in-20.
Quick, easy, intuitive, and the math is nearly always single-digit addition until negative ACs start showing up, at which point a bit of trivially easy subtraction enters into things.

Part of the whole "renaissance" thing is rediscovering the parts of the old days that weren't so bad after all.