Sure, it's easy to just pick one of the better teams, choose a formation that fits your squad natural preferences and assign roles that are better suited for each player, but you need to think more deeply about the relationships between each member of your team. Let's face it: sometimes certain Players just won't fit in with other members of your team, or even the type of system you are trying to implement as the new manager in town.
In Football Manager 2017, you simply cannot throw your higher rated Players onto the field and expect everything to just fall together. Sometimes you're going to have to mix up your roster, and sometimes you're going to have to get rid of a few players that either won't get with the program or simply doesn't fit properly with what you are trying to accomplish. And sometimes, this doesn't just include the players, but also your office personnel as well.