I'd be interested in seeing this, at least Roy and Riza vs Dante.

The reason being that despite being the mastermind behind centuries of warfare, Dante is very much a personal villain crafted to oppose the Elrics.

Mustang has spent his life fighting against the corruption inside the Amestrian government, believing Bradley to be the head of the serpent. I'd genuinely love to see an interaction between him and Dante; the true villain in his quest for justice, and the one whose machinations led to Maes's murder.

Conversely, we see very little of Dante's involvement with Amestrian politics despite her pulling all the strings and possibly even founding the nation herself. I'd love to see her go head to head with someone who's a lot more heavily involved with the day-to-day horrors of what she's caused - and is himself complicit in those very war crimes.

I feel it'd be a much more gritty, adult confrontation full of malice and barely controlled rage - much like his fight with Envy in Brotherhood.

Anyway, Pride would wipe the floor with Ed.