There are 2 problems with that.
The first is, one shouldn't have to alter their style of play to win. There is one goal in mind. Checkmate the King. It shouldn't make any difference whether you do it by grabbing a pawn on the Queenside, and using your majority to distract your pieces and then win down the middle, or if you have some stupid fireworks display where you find some cheeky mate.
The second problem is that what one defines as an endgame is subjective. Some say a trade of Queens is an endgame. I surely don't. 1.d4 d6 2.c4 e5 3.dxe5 dxe5 4.Qxd8+ Kxd8 is NOT an endgame
R+5P each is an endgame, but what about R+B+5P each? What about R+2B+5P vs R+B+N+5P? What about 2R+2B+3P each?
Also, one should play the best move every time. There are times when the best move is to offer a queen trade. If you think that a game is too boring or unplayable with the Queens off, take up Tic Tac Toe!
I've come to the opinion that the highest levels of chess can unfortunately be very theory deep and lacking in exciting attack and risk taking like chess of previous generations (such as that of Tal). Obviously such players still exist, but tournaments today seem to be more conservative for some reason. One extroadinarily simple change that can make tournaments much more conducive to exciting and innovative chess would be to change the point system.
I've always thought that players who were able to succesfully attack and win without advancing to the endgame had scored a higher victory. It takes extra risk and innovation to succesfully do that. So why not rewards it? How about awarding players who reach checkmate before the endgame 1.5 points. Additionally, the value for a draw can be reduced slightly, say to 0.4. The second rule does not necessarily need to be adopted. By "before the endgame", what I mean is if the player has not promoted a piece, or if the game has not yet reached it's 25th-35th move (this would need to be determined).
Now when would this be applied? I'm sure that the chess world would be up in arms if this was adopted everywhere, naturally. It could simply be tried out in special "attacking" tournaments. The result would surely be more innovation, adoption of more attacking lines and more exciting, aggressive chess. This certainly would not be universal, as I do appreciate long-term strategic games as well.
Thoughts?