Actually, to be clear, I do enjoy Pathfinder 2E in the moment. But I had a real breaking point the other day when I was contrasting my PF2E campaign against the somewhat less frequent but more fun OSE campaign. The specific scenarios that arose were as follows:
1. I had worked out a number of planned encounters that would be ready for me to use when the time was right in the PF2E game. But this shined a light on the more RNG-friendly encounter system of OSE, where I actually had sections of the scenario that said, "This room has a random encounter from Table X in OSE" type stuff (or the B/X books specifically). The players invariably were having more fun with the decidedly less certain encounters in OSE due to the fact that the game system by design could flex with a measure of uncertainty and randomness that is hard to accomplish in PF2E.
2. The second situation involved one of these "built but held until the time was right" encounters, a technique I use to have something ready but held for use when the situation/player choices call for it. This is a necessary technique in PF2E, which by design does not favor random encounters, encounters that fall outside of a certain balance range (which if you go too high or too low leads to tediously easy or insanely hard/lethal results), and the books themselves do not offer up randomized encounter or loot tables.
Anyway, the prebuilt encounter was missing the loot...I had fogotten to figure it out, or misplaced it, and so I had to improvise on the fly, which is "technically doable" but its pretty obvious I think to the players I'm just trawling through the confusingly organized loot tables trying to find stuff, and also make sure that stuff is level-balanced, another issue with PF2E where handing out loot that's too powerful too soon or too weak too late leads to further power/performance issues for future encounters. It was a pain in the ass; in contrast, the treasure tables in OSE (B/X) make no assumptions about balance; its all about luck, and sometimes things go very well for the party, and other times they roll a cursed item, or maybe the monster hasn't accrued any treasure at all. It can swing both ways....and its deliberate by design. This is a much more interesting result because it means two different games in the same scenario can very wildly from one another.
3. I had some NPCs I wanted to design, and I figured I could build them in Pathbuilder 2 and then turn them into statblocks. This led to a moment where I was reminded of just how much I hate the nit-picky nonsense of feats, especially skill feats, in PF2E. There is no analog here in OSE; you get abilities by class, but not very many, and most of your character's "character," if you will, is determined by actual play, deeds, luck and cool stuff you might find or do.
The two feats that broke me were (without recalling the exact names) one in which you remove a specific penalty against being attacked while climbing, and another where you can take a Step action into difficult terrain. The first one got me to thinking about how rarely a situation has cropped up in 3rd edition era games (and I consider PF2E to be a descendant of 3E era games) in which you can be attacked while scaling a cliff. Does it happen? Sure, but it is far less common given the predisposition of this era of D20 systems to favor maps and minis, which are notoriously difficult at representing verticality.
The other feat, where you can "take a Step action into difficult terrain," made me actually mad and irritated at the game. First I had to figure out the Step action,* and realized its just PF2E Revised's 5-foot step from classic D20 terminology, probably now renamed because you can't just call it a 5 foot step anymore for some reason. Second was the realization that unless you have this feat, no one, regardless of their acrobatics or athletics skill, will ever be allowed to try for such an action by the RAW unless your GM is like me and actively disdains the skill feat system as nothing but annoying limiters.
More to the point though, it got me to realizing just how many of the feat choices in character design in PF2E are just pedantic little "get out of jail" cards for gotcha rules. It shined a light on why a skill-based system like Basic Roleplaying or a non-skill-based system like OSE (or B/X if you use the optional skill system introduced in the Gazetteers) allow for a lot more storytelling flexibility because you aren't having to fight the rules every step of the way. This might not be a problem for some groups, if you don't have any players or GMs with a sense of rules mastery or rules-lawyerism in their mental perspective, but if you have even one rules lawyer at the table or just a sense that ignoring the rules detracts from the experience, then that can lead to PF2E being very bogged down in these little gotcha bits.
There have been other contrasts that broke me a bit. I tried working out some potent magic items in PF2E but realized the only way the game is mechanically comfortable with allowing such flex in items is through level scaled relics. OSE doesn't care; you can stick the Nine Lives Stealer from AD&D into a gang of level 1 PCs and consequences be damned. Can you do that in PF2E? Sure, but the Nine Lives Stealer is not going to be the cool sword you think it is, and if you ignore all the design expectations and just make it happen, its going to make one player in that group far more balance-wrecking for the rest of the party.
There are things I like about PF2E, but the devil is in the details. My love for the game stems from the fact that it "feels" better to play in terms of dice, probabilities and threat/risk than D&D 5.5, but the game's fun factor dies by a thousand cuts for me when I realize how much of the game is dedicated to micromanagement, niggling exception rules, and artificial limiters designed to prevent players from doing stuff (not even cool stuff, just regular stuff) all so the mechanics can induce the illusion of choice through its labyrinthine feat system.
The problem I face is....I may be having issues with PF2E, but my players on that night do seem to enjoy it. Only one of them is in my OSE game (the rules lawyer, ironically! But he loves OSE as well and its got plenty of rules, too) and I don't know if I could convince them all to give OSE an earnest, permanent try.**
So all of that is why I say my fascination for OSE (and Shadowdark, and DCC) is not nostalgia driven. In fact if anything I keep entertaining the notion that deep down, in terms of complexity vs. ad hoc flexibility, D&D 3rd edition (and even Pathfinder 1E) managed to handle this better than PF2E. But those are dead systems, and hard to get a group into these days without being able to point to a virbant, living character creator (hmm, I think the original Pathbuilder may exist, though....) but also I just really love OSE's revival of B/X, even though I never really played B/X in the 80's, using it instead as a rules system cypher for interpreting and resolving Gygax's particularly confusing rules moments in AD&D instead. In a way, that works in its favor, as actually thinking about playing AD&D 1E straight up just sounds....unpleasant....to me, thus why I love how OSE's blend of B/X with advanced options "feels" like the game I used to play, even though its really just a sort of approximation of the zeitgeist of the era.
Anyway.....just some thoughts! I'll bring up the idea of OSE to the group tonight.
*So for reference I have been running PF2E games since it came out, including one game that ran from level 1 to 20, and yet seeing "Step" in text threw me for a loop; this is where the "I'm getting too old" part comes in, as in "Too old to remember all these dumb little rules." It also probably doesn't help that I run theater of the mind in PF2E as I am too old and tired anymore to drag many pounds of maps and minis around (and also too tired to spend hours designing VTT environments while listening to everyone try to talk at the same time on a single audio channel," so thus the old man yelling at clouds vibe at this moment.
**I could probably convince them to move to Tales of the Valiant, though. My group is fairly in agreement that D&D 5.5 is now just too banal, unchallenging and simplistic for veteran players, but TotV manages to capture a sense of natural progression and improvement from what regularD&D 5E used to be, so this may be a good option.

