I would just check your bags. Not suggesting that you don't travel light, just that I can't think of any benefit that would make trying to achieve 7kg worth it.
Assuming your only transit point from your home is Dubai, then the chances of anything going astray I would consider low (if that's your concern). And unless you are a team in the 'Amazing race', I wouldn't be worried about how quickly you get off the plane, through immigration etc. You'll all be in the same line and most likely your bag will be waiting for you rather than you waiting for your bag.
For me, getting rid of your bag at check in is one of the nicest parts of the long flight- as it's one less thing to think about. I then just have a few bits that fit in a bag that easily sits under the seat in front. Emirates has good food, decent blankets and fantastic entertainment - you won't need masses of stuff.
The other benefit is going through security is easier with less stuff (liquids, electronics etc) and travelling between gates in Dubai airport will be easier (can be lots of walking and up and down levels, especially if changing terminals).
I suspect that the (almost) obsession on this site with not checking your bag could be to do with the risk of your bag not arriving with you when you travel from smaller US airports to connect at a bigger hub. Or is it that they charge for hold baggage? I've noticed that flights seem to take an age to board in the US with everyone lugging massive bags into the cabin and trying to stow them.
To sum up, if I were you, I'd focus on travelling light, but not that light.