He's at a similar level to McTominay. They're both top class but at only a narrow range of abilities.
In McTominay's case, it's pressing, shielding the ball and (uncreative) short passing. In Rice's case, it's screeing the defence, tackling and (uncreative) long passing. Both players are good enough to be cogs in world class teams, but neither is world class in their own right. Also, they're both cogs that can only fit into specific places in functioning XIs.
If we stick with McTominay, we need a creative DLP and a hardworking creative AM (so two purchases). If we go for Rice, we need two creative B2B midfielders (three purchases altogether). Which all means that McTominay and Rice not good enough to play together since their weaknesses are so similar.
From a financial point of view, it makes sense to stick with McTominay and build around his engine. So although I'm a fan of Rice, I think he'd need to be part of an unrealistically big overhaul.
United are already playing catchup. If Rice is part of the solution, it would be a step forward and a step backward at the same time. Let's just keep McT and let him do the dirty work for a couple of new faces.