Nah, play the latest version.
My main problem with DoomRL these days is that it's a bit too long for the amount of content that it has (it's 25 levels but gets kinda boring after 17-18 levels).
This could be fixed by either making the late game more interesting, or making the game a bit shorter - but it's still pretty much my favorite roguelike so I'd say whatever flaw it may have it's worth overlooking for all the stuff the game gets right.
I was never really bothered by the unlockable stuff as it's mostly not stuff I'm hugely interested in when coming to the game after a long while of not playing it (or, I suspect, had I played it for the first time when unlockable stuff were already there).