I share your desire to have a realistic football game. Lord knows that shouldn't be too much to ask.
The problem is that creating a game
better the HC09 would be an immense project,
especially starting from scratch. Creating a text based football game that was realistic and with a decent career mode would take six months of full time programming work for one person. The guy who created Front Office Football was such a person, and if you look on his web site he tells the story of how that game came to be.
If you want a graphical 3D football game, look at Maximum Football (Matrix Games) created by a guy named David Winter, I believe. The graphics probably date back to 2001 and there is no career mode. He has been working on the game for years, full time.
So, basically what you ask is not practically possible. No one is going to work full time for years on a project that will be given freely to others. Then there is the license issue. In order to use any NFL logos or players/teams in a game, you need an NFL license. Licenses are only issued to corporations that are well known and trusted not to make the NFL look bad in a poor product. Im sure it also costs money, probably alot. The only way to use NFL teams/logos are third party mods.
And this leads to the modding question. EA has always discouraged modding. The only mods I have ever seen for Madden are minor graphical ones.
You have to understand that its not fans who run EA or EASports, it is people who dont play games and can only read spread sheets. Unless it is uttery obvious something will make them more money, they will not change a thing. They wont let people Mod Madden or HC because they believe it wont make them any money. Thats it, period. No other consideration matters.
My personal feeling is that EASports will never allow substantial Madden Mods because it would be too easy to make the game alot better. If it takes only a couple of months to create killer mods, people are going to wonder what the hell EA does all year.
If mediocrity makes money, mediocrity is what we are going to see. That is Madden in a nutshell.