Calthropstu
Villager
Not sure what you mean pf monsters were boring. I can pull a dozen different monsters and make each a completely different fight. At high levels things can get absurd. I put 4 derghodarmons and 1 phasmadaemon inside a complete illusionary fortress. Completely wrecked a 16th level party. Fear, illusions, mind affecting, shapeshifting, beatsticks, summoning, teleportation... monsters in pf have the widest array of abilities of any d20 system.I published ZEITGEIST in both 4e and PF, with me writing about 2/3 of the adventures in 4e first (and then it was converted to PF), with the other 1/3 written in PF first (and then converted to 4e).
The conversions always had trouble in tiny ways. First, like, Pathfinder monsters were f'ing boring. It's just how 3.5/PF/5e is built. Monsters suck. They don't do anything interesting. 4e monsters had much more interesting tactics.
Second, PF magic was so much more flexible. If wrote an adventure in 4e, my PF conversion guy would remind me gently that, um, the PF PCs would be using scrying, teleportation, divinations, passwall, etc etc etc. A lot of plots had to be rejiggered to make sure interesting scenarios in 4e didn't get solved trivially by PF spells.
Third, 4e didn't differentiate between magic and non-magic, and there weren't 'spell components.' In one adventure, the PF author wrote that the villains cast silence to sneak up and prevent the PCs from casting spells. Well, that just doesn't matter in 4e.
So yeah, it's not easy. PF2 to 4e might work. 5e to PF1 might work.
So I don't see it. But regardless, I DO see what you are saying about abilities in one system trivializing an encounter that would challenge another system's party. Or conversely overwhelm them.
And I agree such power disparities need addressing. But the systems themselves provide such tools for a good bit of it. For example, I expect a pf/3.5 character to fight a pf/3.5 demon. While a 4e/5e character or gurps character to battle a 5e/4e demon or gurps demon. So the abilities should be comparible vs the creatures. Granted, it takes more system mastery than mere monster conversions or bestiary entries. But I suspect such challenges can be addressed in system.