Just because MyTeam is like that doesn't mean that it has to be. They could offer a lot of different game modes with different kinds of restrictions. A lot of guys in the MyTeam forum here on OS are sim players who enjoy playing with legends, tinkering with different kinds of lineups, and enjoy the collection aspect of the mode. A lot of us create and play with theme lineups. An online mode that pairs you up against an opponent of similar strength teams or one with more restrictions akin to the first RTTP seeds are being asked for constantly. Furthermore, there's a different kind of irrealism in having a lineup full of HoFers vs a lineup of fantasy cards to begin with.
Speculation: To me, it seems like the source of the majority of problems of this game mode stems from the fact that nobody on the staff has spent more than a few hours playing MT. Because many of those problems become obvious pretty quickly, with a decent percentage of them being legacy issues. The fact that they're not being addressed makes me think that nobody on staff plays MyTeam, because if they did they would have done something about those glaring issues after 2-3 years.