Also being able to position yourself on the pitch/between the lines to be able to receive the ball consistently is far from a given, and something Havertz seemed to struggle with especially. Large parts of the game would completely bypass him with him in MF. Indications are that Merino will thrive in those areas, in comparison.Merino is happy to come and receive the ball on the half turn, is press resistant and constantly looks for a forward pass. So he'll be much more suitable. Havertz clearly wasn't comfortable in the role.
Also we're becoming a really tall team now. Another 6'2 player to add to Saliba, Gabriel, Havertz and then there's our new Italian