Its not so much formation as much as its little variety in how we play, and a recognization when changes are badly needed to our approach during the game. Formation wise, you're right, there is alot of variety between 4231, 343, 3421 and 433. It's the approach that he needs to adjust. It is largely his in game management, from subs down to approach.Not sure about lack of tactical variety. He hasn't used 4-4-2 too often true, but he has used 4-2-3-1, 3-5-2, 4-3-3 & occasionally 4-1-4-1 when thought it warranted it, so I'd say fairly tactically adept.
Mind you, I'd prefer him to decide on his best formation tactically & let the opposition worry about us, rather than changing things around too much.
Wrt 442, football has largely gone away from a 442 with 2 speed demon wingers staying on the wings. Wide midfielders/wide forwards are cutting in more and fullbacks command the touchline. If you see a 442, its an inverted 442 that looks more like a diamond with the wingers also cutting in. You dont see a flat 442 much anymore unless a team completely sits back, in which case, its more a 4411 then a 442.