No, not having them will not be a mistake. It would be good to have them, but the game simply does NOT have a market big enough to pay for the Be A Pro mode and Management mode would be also take a big chunk of development time too.

I've probably said this a few dozen times on TRF, but Fifa is made on a huge budget of many millions of dollars. This game possibly has less than 10% of Fifa's budget. How on earth do they do all these things people want? Do they just decide to not pay their staff and stop work on other projects?

A management or franchise mode would be nice, but if they start work on it, then time goes away from making the game play correctly, the AI from being better than it's been before, from the graphics looking any good. I don't think anyone with common sense wants the game to have a whole bunch of features and none of them function very well.