Among the numerous ideas for season 5, one was an encounter with Flint in one of his earlier aliases.
I'm curious whom they would've gotten to play the role. Supposedly, when casting T'Pau and Surak for "Awakening", they consciously cast actors who at least somewhat resembled the originals. One would hope they'd do the same here.
Personally, my choice would've been Tim Daly, being the son of James Daly, the original. Admittedly, he might've been a tad expensive, being a fairly popular TV actor, and may or may not have been comfortable taking up a role his father played.
Still, we can hope.