People typically are referring to OD&D and the Basic series when they say Old School was simpler, not AD&D and definitely not AD&D second edition. If they do use ad&d as a reference point, they ignore like 90% of the rules as optional.
Old school was birthed in 1974 and died at your choice of...
I ran the premade module in it to decent success. Trying to use the campaign tools was frustrating and I ultimately gave up and pivoted to a different campaign frame. It ultimately is a better book to steal ideas from than to use as the sole source for a campaign, imo.
The art, design, and ideas in LL's stuff is really really good. They're very fun to read or flip through.
They tend to lack polish/specifics though that make them more challenging to use for actual play as-is. Specifically I tried to run Wind Wraith which was very challenging to use and...
I can attest to this. The PF1 campaign I was in broke down for this exact reason around level 9 or 10, where the DM physically couldn't keep track of the buff/bonus/etc in an encounter where he had to run multiple spellcasters, and had like 30 tabs open in his browser just to try. This was...
As some examples of early game complexity. How do you draw a weapon or potion?
In PF1: you can draw a weapon as a move action, which means you can't move during your turn. But, if you have a BAB of +1 (like a level 1 fighter), you can draw a weapon as a free action during a move action in...
Maybe 2 hours, then I started running the game. I had my group(s) read the rules and we started playing immediately, pretty well without too many issues.
I have also had a group NOT read anything and we learned-as-they-played through the beginner box. Again, no issues.
My advice from running multiple campaigns with OSE:
Your Table Will Vary. Change the game as needed while you play to make it more enjoyable for yourself and your players - talk to them about what they do/don't like. Don't do something a certain way just because you've seen it done that way...
As much as I prefer the rules actually present in Moldvay B/X or the all-in-one package of the RC, Mentzer's BE was absolutely better for actually teaching the game. Absolutely fantastic work.
It doesn't have torch weight, because the weight of individual adventuring gear wasn't defined until the Mentzer Expert set came out (1983). In Molvay/Cook B/X (1981), all adventuring gear together, regardless of quantity or type, counts for a total of 80cns of weight. You quoted that exact...
To make a system like this work,
This needs to resolve instantly, not over time like death saves. It should be a straight 50/50 shot of instant death.
Reason being is that otherwise, the optimal choice is always choose this option, then wait for a party member to heal/stabilize you - that is...