@brucewayne based on where Richarlison played at Watford, I'd say he'll play on the left, with Lookman and Walcott (ideally) competing for either flank as well. It'd be three very good options, possibly throw Dowell/Vlasic in as well (or, dare I say it, Kev...).
I want Lookman to stay Lou, but him and Richarlison aren't similar players in terms of style, even though they'd probably play the same position in a 4-3-3. Lookman is more skilful, and I'd say better in tight spaces. Richarlison has pace and power and that knack of getting in the right position to get on the end of something, albeit after November he didn't put any of them away. He's also versatile and can play as a central forward if needed.
