I appreciate all that Gavin Norman and Necrotic Gnome have done for the OSR TTRPG scene over the past few years, but I have to say each time I see a D&D-derivative system it makes me wish that other systems of the time—like Runequest, Tunnels & Trolls, or West End Games' d6 system beneath Ghostbusters (1985) and Star Wars (1987)—got even half the attention. Tom Moldvay and Dave Cook's Basic/Expert (1981) has been don…
At least BRP (the system behind Runequest) and d6 are actively developed and there are games, new and old, using them. They are also rather popular, at least if one browses rpg.net. T&T I don't know. I think there is a new edition coming along?
My point isn't necessarily that there shouldn't be modern versions of these games—obviously, D&D is the most popular TTRPG (at least in the US), and itself barely resembles the three brown booklets of '74. It's that by going back and discovering what made the originals so great, we can carry these lessons forward and make loving modern interpretations like Old School Essentials/Dolmenwood.