if you get a different router contact the manufacturer and ask if its running upnp idg2.0, older firmware's are not fully compliant and the game has coding that requires its use to work properly, the only restriction this creates practically is you have to dmz the console and remove any other forwarding rules, blops3 is in the same bracket and no I don't personally know if any of the routers on the market are any good.
with respect to the internet dropping, the problem with using dmz is you open your router to attacks so people can spike you and force your router offline or do other things, its not uncommon for someone in the gaming community to use such tactics to gain an edge over others or to create space in a party.
getting a better router that supports the additional requirements automatically without dropping the security steps will prevent the average script kiddy from being able to do this /
just because your paranoid doesn't mean they aren't out to get you
