Pretty sure they have said no Dante demo.
And a Dante demo would be the worst thing to do if they want to actually sell copies for the game. Most people are going to get Dante, will just get overwhelmed and then come on the forum to complain. It's also considerably harder than the Nero demo as it happens later into the game, I have seen journos play the Dante demo and died 5 times in a row to the boss (zerg style, not even talking about respawn) then proceed to complain about MTX or some dumb shit. There are already people who think Nero is too "clunky" or "stiff", whatever they mean with those qualifiers that's going to apply to Dante even more so since he is more mechanics and skill heavy.
Gotta ease players into Dante now since his options have become so vast even at base level.