After discovering that there is no dedicated Nolt post for this concept despite being talked about alot, here it is.
Additional arm/manipulators in both full and sub arm versions. This option can lead to a variety of things such as simply holding more weapons of the dual wield type for more firepower to multi wielding weapons of different types.
Having the additional arm/manipulators hold shields can also give way for 2 hand gun and shield playstyle or 2 melee and 2 shields. I believe that the shields should be automatic in defense to absorb damage to the point where they have to regenerate or otherwise they break and have a large cool down. They can be turned off and on to manage damage absorbtion.
A drawback to Additional arm backpack/frame would be increased ammo usage [if they are using multiple ranged weapons at once] as well as drastically more weight with how much is being carried and the arms themsleves [assuming lots of weapons are in the loadout]. Of course the increase management of your weapon systems is there too but personally I would love more complex gameplay aspects on the line of weak at first but powerful when mastered.
In order to comply with the devs want for frames both confirmed and suggested to be compatitable with maps of varying levels of verticality, for example the dam mission. I imagine that the frames overall design being similar to the Skeleton frame to have more built in thrusters to the frame as well as it be a bit bigger in order to make it logical for it to achieve flight. As well as maybe more in game lore of it having another Vermillion energy reactor than the standard 1 to comply with the increased power consumption.
Feel free to comment your thoughts or add onto it!
Imagine: additional arms + bare-knuckle brawling
Funny Therex posted a picture of Asura.
As I was thinking of a multiple armed M.A.S.S frame, code named ASURA.
Another name which was suggested by Kahni was DURGA.
Also with the arms you could go with 2 melee and 2 range, where your focus / lock on mode can fire the guns, or have it so guns could fire at the end of a combo, dealing some extra damage or inflict the status effect they have.