Why can't we have both and the people who want to play each type of game enjoy what they like.
I personally haven't found SF or D4 to be a slog. D4 remained fun for me though the story and clearing the map which took me up to lv60 and then I put it down to pick up again later, SF is a long game but I haven't felt like I've had to grind or repeat content to keep up, everything I've done is a bespoke quest and that's given me enough experience and cash to level up what I want and buy a top level ship, etc
If you don't like long games you may well find those games a slog but then you have games like the new Assassin Creed focused at people who want shorter games.