Multiplas are awesome! Not many cars win Top Gear best car 2 years in a row.
I've got 2003 Cooper with sunroof and my F55 will definitely have one, the opening thing is a bit of a red herring, I rarely open mine. It's the light and 'airiness' it brings that's great (if that's your thing). I'd prefer if it was just a glass roof like you can get on Citroens et al.
No, No, No, No.... Multiplas are NASTY, HORRIBLE things
The only people who say they are good are the people who own them, and they are only good because they solve the problem of transporting more than 5 people.
Apologies if this offends but I do have two fully operational eyes