Is 4-5-1 a good formation and what are the weaknesses?

[Michael Jay Jay Jolliff]

???

[July Fourth]

???

That is infact the newly common 4-2-3-1 formation that football sides use today, where teams can make players attack and defend in many different situations, Theres only one front man but with 3 possible players to support him in a attack and like wise they can send players back to defend, this formation by many is believed to be 4-4-2's successor. The weakness is attacking players need to get back and defend.

4-2-3-1 Soccer Formation

[Lee Miller]

I've no idea how much the game reflects real life etc but 4231 is supposed to be a very flexible formation. It is played with 2 CDM though not 2 CM and the middle CAM should really be a CF but you have the arrow to run forward so that would reflect that better.
Perhaps try having one or both of your CM make more defensive runs back.

[Aaron Ramsey Tiong]

No, this is exactly the 4-2-3-1. Your formation would actually be illegal on T11 as there's noone in the MC row. :/