The MDR is a neat looking gun. It’s had a few teething problems but most seem to have been rectified. The forward eject mechanism does seem a little finicky for a military rifle, but at least some of the problems seem to stem from the wide variety of ammunition types it has to deal with on the civilian market. A military rifle ought to have a more consistent ammunition supply.
I think to make it more "sellable" they introduced the side eject option which is a far simpler mechanism and can be switched from right handed to left handed in mere seconds. ( as you can tell, me likey!)
Where once the size of bullets got smaller, designed to injure rather than kill, take three Men out by shooting one, overwhelm the Medics, break morale and of course you could carry more ( The G11 is a good idea). This new type of "warfare" needs something heavier, as these "People" do not care about casualties. So, in my unqualified view, HK416 in 7.62 would be the best choice. As a left hander I could just about pass my APWT with the SA80, pissed it with an SLR on iron sights.