I don't know what you're complaining about. In my opinion, you should do exactly that. In fact, you could even steal players from City, and then they'll have even less of a chance. That being said, the only players worth stealing from City are Silva and Agüero. And then get a decent keeper and central defence as backup to Reina, Skrtel and Agger, maybe if you've got money left a decent centre midfielder because Shelvey is terrible, and voilà! You've got a Premiership winning team. Then, you know, when you start losing, just blame the match engine like everybody else! It's definitely not down to the fact that you just completely reshaped your team.
I was actually being deadly serious before I got a bit sarcastic towards the end, but that's what will happen. Your team will have no cohesion as a unit if you start splashing the cash. Although, that's not to say you should start a new game just because you've got money to spend. Make a few sensible purchases and save what's left.