This has been my stance ever since the GM mode was instituted one year (2006?). Have an "Arcade Mode" or a "Season Mode" where you can play the traditional way and assume a character and fight your way to the top but complement that with a television style GM Mode. The GM Mode was here today, gone tomorrow. I was hoping for some serious advances in it and one that would take it from being a fictional GM role to a real-world role. Let me, as the player, book the matches and set the feuds, rig the outcomes, etc. I liked the competition aspect of the original GM that pitted you against the other brand's GM. Keep that, and as part of the set-up have it be something where McMahan tells you he wants you create the best product and best the other brand's GM. This wouldn't be entirely realistic, but it at least gives you some incentive.
From there you plan your shows and feuds and are awarded ratings after each show. Like the previous GM Mode, it could keep track of rivalries and the fan interest associated with them. To add difficulty you would also have to manage each superstar's personality. Sure you may want Undertaker to drop the belt to Edge but maybe he sees things differently? Unhappy characters lead to bad promos and matches affecting the product. And at any point you should be able to play a match you've booked.
This mode could even be tied into a lesser mode where you select one character and have to do as your GM says. The idea being the better job you do the more likely you are to get rewarded with a title run. The matches could have specific goals in them (e.g. - Get thrown off the cell, bust your opponent open, knock out the ref, etc.) that if attained, affect your performance. This could even be a mode for created superstars only and attribute points are awarded based on the results.
At any rate, that's where my head was at following my exposure to the original GM Mode and since then the mode has been dropped and I haven't purchased any new WWE games. I've felt for a long time that the gameplay was fine and some tweaks here and there could make it truly fantastic (never felt like the weapons had enough interactivity or did enough damage), especially with better AI. The problem is the games just don't contain enough features to keep me playing.
I should clarify, I don't blame developers for a sports game becoming stale. Even though wrestling is not a sport, the games have adopted the same release pattern. A great deal of money goes into securing the WWE license and the only way for THQ to profit from that is to put a game out every year. Short development cycles leave little room for innovation. Plus, the WWE has the final say over how its product is presented and it's quite possible they would not be in favor of a game that too fully embraces the behind the scenes affairs and not the fantasy that plays out in the ring.