I have used blank lineups for the last two or three seasons; I liked to watch the game engine adjust the match ups on the court; it seemed a reasonable consolation for the inability of a human managers to make in-game tactical decisions. Since emphasis has been placed on humans making lineup decisions, I've noticed the game engine is much less involved in making lineup changes during the game. It makes the obvious, necessary moves, but there are nowhere near the number of matchup adjustments that one would see previously. I despise the the GDP guessing game also.
For my money, given the very few options human coaches have to make adjustments during the game, I would like to see the game engine revert to making the matchup decisions it made prior to efforts to eliminate blank lineups. There are probably other considerations I do not understand, but I miss that element of the game.