Baseless affirmations aside, I think this is an important issue to address, or at least consider and/or debate if there are any plans farther along to implement powered armor suits which provide sufficient strength and targeting assistance as to allow the use of two primary weapons. This may also be pertinent to later-game alien 2x2 units, and possibly human 2x2s.
Also, paired Laser Pistols have already been mentioned as a feasible use, and if there are any weapons that can be paired, there will be some demand for a system flexible enough to allow paired use for all weapons, even if it is disadvantageous to the point of unusability in most of those cases.
2-handed weapons are not necessarily a requirement in most cases, but more of a suggestion for if you want to hit anything. If 2-handed weapons can never be used together, then there may be need of a new, "1.5" hand class, for SMGs and other weapons that can be held, aimed, and fired with one hand, but have enough recoil to need a second hand for accuracy.