The 275th was created on the foundation of Balance as a principle, in actuality. I agree that diversity is key in maintaining that- both a battlefield balance, as well as inter-Lance and Company balance. With that said however, each unit also has a specific role. If every unit is diversified, we become set up in a way that makes us, while not weak in any area, not strong either.
Most of Hyperion Company is entirely diverse, with the exception of HellBorn Lance, which is a dedicated strike force.
Shadow Company, while still being fleshed out, is likely to fall under a similar principle of having a diverse selection of 'Mechs and setups.
Both units, if needed, can be meshed together almost seamlessly- HellBorn Lance is still just as self sufficient as any other unit because, while they have a very niche role, they do it very well and can compliment any force.
As well as that, the Lance/Company set ups are only primaries- if we were operating optimally and had every pilot online, that is the Company/Lance they would be a part of, and even then, roles are not static- just the preferred role is marked down.
However, we will in most cases be operating sub-optimally. Units will be conjoined with what troops are available, with a preference towards same Company, of course. Companies, eventually, will be part of Battalions, where a preference will lie, and etc. I'm sure in many cases units from Hyperion Company will be operating in Shadow Company, and vice versa as the situation requires.
There is also the matter of reinforcing weakened areas, once faction warfare becomes available. I've taken all of that into account in that units will need to be shifted from one area to another in order to hold a key area, for instance.
So! To sum it all up for you, what you've said is entirely accurate- we do need diversity, just as we need specialization, but I think it's a flexibility that we already have, even if it's unspoken. If we had a Company set up that, by chance, was comprised entirely of Strike troops, we'd shift roles for the people that have cross training.
I hope this has cleared up any concerns you have, though I encourage you to make your opinions known. I'm nothing if not open to the thoughts of my troops, and I consider their thoughts highly important to the efficient running of a mercenary unit.