This has to happen. In the last decade there's been minimal innovation in the single player arena.
A manager mode is easily the most logical path of progression. Even in real life the pack mentality and gym personality is just as engaging as the personalities of individual fighters.
Growing a brand and cultivating talent is far more engaging than taking a single player up a point oriented ladder.
Its time to come to terms with how antiquated the single fighter mode is and start looking at how much more enjoyable the experience could be as you train and grow a number of fighters over many disciplines.