Depends how good your team is tbh if your like 7-10 quality better than your opponents then play what you want i say, no need to change it. Plus people are saying that certain counters dont seem to be working anymore. Some players can and will just start playing **** for no reason, ive a MC bought the middle of last season and he was rating 8/9s, was one of my stand outs. Fast forward to this season and hes rating 5/6, no reason for it, full morale playing the same role (unless it has something to do with the players around him. Changing your formation wont harm your team, unless the players are worse than the ones they are replacing or there morale is ****
Basically, its upto you to form your own opinions, the amount of stuff you read on here that has little or nothing to back it up is unreal, its basically peoples opinions with no solid evidence that what they are saying is true