By semi-Newtonian...is that like the physics in the old version of Lightning Marshals?
Yeah, pretty much. I also once made a tablemod (Realflight on FSMods IIRC) that does something similar for FS2 proper, blatantly abusing Sushi's velocity mod and hacking some BtRL-style damping and side strafing on top of it :nervous: (although originally FS2 also had side-strafing, but only for the Shivan ships and the Terran Mara). Ultimately I don't think it works *that* well, as such speeds and physics don't really mesh well with FS2's aesthetic. The flight model itself is still great fun though, especially in it's BtRL and Diaspora implementation. It might be a lot better now: Fury AI didn't exist back then, and IIRC it's a lot better at handling faster ships.
There is another reason to try out BtRL, and that is how intrinsically fredded those missions are, in ways that are not immediately obvious. People have already mentioned the voice acting: It's brilliant. A lot of AAA games don't get people talking over each other right, BtRL does. It's worth replaying that campaign too, as it has a few neat surprises.
The game reacts to you breaking the mission by trying to prevent the "scripted deaths" which, actually, you can! Or you fail and you get chewed out for disobeying orders. Which is neat! It's a pity I had to find out by digging trough the FRED file itself though O_O