If the person is TRULY good, then sure there's respect. But how many people who run around with these things really ARE truly good? If you were to take away the MP7 and Akimbos or the other common things people tend to use, how much will a bunch of peoples' stats and scores suddenly drop because they're now completely out of their comfort zone?
I'd say that's another thing my Randomizer mode idea could be good at; really rooting out "better" players since, if they're truly that good, then they should be able to work with whatever they're given and still come out on top. Too many times I see people make claims that they're "beast with any gun/setup" or something, yet continue to stick with whatever's the easiest.
I sometimes use the FMG9's I admit, but only when I am going for a MOAB and my Primary is a Semi-Auto or a Burst Fire weapon. With the MK14, it would be silly not to choose the Secondary weapon which is the best back up for close range encounters in tight areas of the map. Do I feel like a douche using them? Yes. But when they prolong my MOAB streak I don't really give a crap at the end of the day. Would I use them with another weapon, like say the ACR or even the MP7? No, because I feel these are decent enough at close range that I don't need an 'insurance policy'.
I don't see how the MP7 should bother anyone. I have over 10,000 kills with it, but honestly it is one of my least used guns these days. I keep it as a go-to class under extenuating circumstances, typically equipped with extended mags & silencer. It will lose CQC to several other SMGs (especially RF PP90 or UMP), but for overall use on any map at any range, it is deadly accurate and with extended mags you have plenty of lead for everyone.
As for the (akimbo) FMG9s, they are one of the most annoying classes in the game. When the game came out, the expert advice was to use them, so I did. Knowing that I am not a great player, when I was pulling off triple sprays more than once a game with them right off the bat, I knew those suckers were deadly. I can live with it when guys use them as secondaries, but when guys run around with them full time it can be irritating enough to make you change to a class to slap them down.