For a moment, I though they were going to bring this game back:
I had a friend who had it, it wasn't too bad (it was a lot like Joust the boardgame), but whoever had the high ground usually won.
Also, besides the modules that had Battlesystem scenarios (DL8 - Dragons of War, DL12 - Dragons of Faith, DL14 - Dragons of Triumph), there was an entire book that was a chit-based wargame that covered the ENTIRE War of the Lance in DL11 - Dragons of Glory.
Birthright had it's own system of mass battles as well that was a bit more abstracted than Battlesystem, but meatier than the mass combat system from the War Machine mass combat rules from the basic Companion/Rules Encyclopedia. There was also the Chainmail skirmish rules from the 90s (and a Battlesystem Skirmish rules set from a few years before), and of course the D&D minis battle game (with mass combat in the Miniatures Handbook) - and that game system itself had a spin-off game with a few boxed skirmish sets during the 4E years.
And then there's always Battle of Nerath for a Risk-style fix.
(All of this begs for a thread about the various D&D battle games that's more in-depth)
Curious to see what this version will be like.