The direct driven fan will move at least as much air as any clutched fan, if not more. The tropical fan clutch (or any fan clutch) can only ever spin the fan as fast as the belt will drive it. In other words, the direct driven fan always runs at the same speed that would be the maximum possible speed of any fan with a viscous clutch, tropical or not. In still other words, when the fan clutch is engaged, a clutched fan BECOMES a direct driven fan.
The difference is just that the clutched fan has the ability to disengage the fan drive in low cooling demand situations (e.g. light load and cool ambient weather), when extra airflow from the fan is not needed, whereas a direct driven fan runs at all times when the engine is turning, regardless of whether fan operation is actually needed or not.
Adding a clutched fan to a 240 would be an upgrade in the sense that it would make the car run a little quieter when the fan is not engaged, and would maybe give a very marginal fuel economy benefit also when not engaged. But it wouldn't add anything to the engine's ultimate cooling capability versus the direct driven stock setup, and when the clutch is engaged the other two benefits would not apply either. There would be no cooling performance advantage from adding a clutched fan, tropical or not, if that is the reason for considering it.
Why the 7 series got the clutch fan and the 2 series did not? Good question, who knows. Might have mainly had to do with cost, as the 7 series had a higher sticker price and might have had more room in the budget for extra features aimed at refinement like a viscous clutch for the fan (or a turbo on the diesel engine which the 240 also never got). It might have had to do with the available space in front of the engine also, maybe the direct fan is a little slimmer and fits the tighter 240 engine bay better, but then again I think some people have bolted 740 viscous clutch fans onto 240 diesels with no fitment problems so that seems less likely.
