There is no way the 4-2-3-1 is superior to the 4-3-3 for us at the moment. Unless Pogba's defensive game steps up and even then, why play our best player so far from the opponent's goal. The 4-2-3-1 is only going to be remotely doable against supposedly lesser teams and even then, on the counter, there's going to be players running at our defense if Matic gets drag out of position. Take a look at the Newcastle game, the goal they scored was due to the vacated central area. Why take such risk? Get a solid CM, pair him with Matic. We get better solidity, Matic doesn't have to run his socks off and Pogba gets to stay higher up.
The only scenario where i think we should contemplate playing a 4-2-3-1 from the start is: 1. if we get Lionel Messi, 2. Playing at home against a supposedly weaker team.
We should build on the 4-3-3 formation as our default formation.
Oh btw, your argument that 4-2-3-1 provides a greater attacking potential doesn't really hold if we get a top notch CM and pair him with Matic. We need greater presence and control in the center of the park. Most of the time, i notice that our shape turns into a 4-2-4. That, imo, is not ideal.