If that is true, and my feeling is that it is (video that showed creation zone points this way), then it is truly inexcusable and unacceptable. I don't play EVERY other sports game on the market, but I'm nearly positive that literally every one of them has the option to edit existing players attributes/equipment. The option not existing INSIDE of GM mode is one thing, especially if they've learned to simply have goalie pads change correctly when they're traded, but not having it in the game AT ALL is virtually a game breaking offense for me and many others.
There is absolutely no justification for not allowing the customization of our own off line rosters. I can create a bunch of 99 rated players, throw them on my favorite team and then trade away all the grinders for all stars and start a season but I can't alter a few ratings that I disagree with (which almost always applies mostly to aging players that EA rates too highly based on performances from several years ago, or young players who exceed expectations and end up on their team's first line in real life but are rated 72 in the game). Why?
And since we can edit our created players, the mechanic already exists within the game, so all it really comes down to is a DECISIONS to omit the feature and that's just flat out unacceptable for me. I would rather have generic arenas, fans, goal horns, etc. and the ability to edit players. Especially when the game logic creates line combinations based almost solely off of ratings so that GM mode can almost never reflect real life (because EAs ratings sick and they are slow to update). The only thing that can actually effect gameplay is adjusting attributes and hoping for more realistic results. Without edit player everything else, from top to bottom, is just polish on a turd.