I guess in theory it's vaguely possible we might see one around the same size 9or bigger) as the Corvette in X-Wing. I'm not going to hold my breath though.
Problem with ships like that (or any mega unit in most games) is that they either overshadow everything else if made vaguely accurate in regards to power level, or are huge let downs if they are made usable (CR-90 in X-wing again....).
They are overwhelmingly powerful that other capitals would basically be of almost no use. You'd have to bring a super-capital to fight it, and then it comes down to "whose supercap dies first".
I know people will bring up examples from novels etc, but lets be honest: virtually no Executor class (there are 1-2 exceptions, but in general)from the EU or movies have died to anything that would work in a tabletop game.
Executor: Freak ram to the bridge. Not gonna happen here.
Lusankya : "Killed" (ok, it got repaired, but still) by a small fleet fighting it on it's own, backed up by an "Q-ship" swarm fgiring vollies of torpedoes numbering triple figures....repeatedly. Not gonna happpen.
Knight Hammer: Destroyed by jedi shenanigans. Nope.
Terror: Killed from the inside, not going to happen.
Vengeance : Killed by a CR-90 ramming the bridge. Highly unlikely.
Iron Fist: Plot-shotted to death by Han and the Falcon. Probably not an option, since if his ability is "Destroy any ships entire shields with 1 shot" he might be a bit OP.
Reaper : Actually did die in something approaching a fair fight....against another Executor-class. So....yeah.
There may be more, but you see what I mean. They are plot devices, designed to be killed usually by other plot devices.