Ok, fair enough. I have a slightly different take on what an "action" game is, but if you guys say it is a game with RT/no pause combat then fine. I can see that.
But I don't thing D&D having the D20 system automatically excludes RT combat. It just would depend on the style of the game. Firstly, RTwP is very much compatible with the D20 system, as the IE games and the NwN games have ably demonstrated. But even if we say RT without pause, what if you want to make an MMO, like Neverwinter for example? I think being very faithful to the D20 D&D system is expected only by classic RPG gamers. But if the game is going to be some game that is NOT a classic RPG, such as an ARPG or MMO or RTS or FPS game, then I think the fans of those kinds of games would not care if the D&D mechanics got modified, even significantly modified, to fit their style of game.
To note, though, I am not saying any of this relative to BG3, because with BG3 the expectation is that it will be a classic RPG in the spirit of the first two games in the series. I am speaking here generally about making games using D&D.