Personally, I find Vassal annoyingly clunky to use and vastly prefer playing over the board. And flipping back and forth on my phone between the rules, the scoring and the cards sounds like, frankly, a colossal pain the backside.
That aside, though...I'm sorry, OP, but competitive anything inevitably comes down to a handful of mathematically optimized options being all you see 90% of the time. Bring all the lagging models up to snuff, some of the current hotness disappears, and eventually we're back where we started. That's just how that environment works.
So frankly, if you want variety, you'd do better to play casual games against casual players. Or come to terms with the fact you're mostly going to play against the same stuff all the time.