Gulla
Adventurer
I definitely agree with this, but Ars isn't by nature very rules light. With players who like (and you trust to) handle the system off screen it is very well suited for PbP, but it's a far bit away from modern/SF playAnd then there's my default suggestion of 'Ars Magica' which I recommend to everyone not knowing the system and looking for something that plays very different from D&D.
I think Ars Magica is very well-suited to be played 'by forum', particularly if you focus on establishing and running a covenant. It also means you have a ton of well-developed minor and major characters to draw on for your narrative.
