it probably doesn't make sense. however half the loadouts really don't. look at heavy mechs: maybe 4-5 configs are actually any good, the rest of them make no sense. close range and long range gear on the same platform, etc. dunno if this is on purpose, but they should probably be juggled a bit.
start with the mech's purpose (frontline brawler, laser-based sniper, laser-based close range, missile-sniper etc.)
then arm and equip from there.
Which leaves us without any generalized mechs. Now, a lot of people like specialized designs, and they are often more effective, but personally I find general-purpose mechs - which almost all happen to be Primes - much more satisfying to pilot. How exciting is it to click 'fire' over and over with a single weapon system?
Try a diverse Prime, sometime. An Osiris, Uziel, Shadowcat, Vulture, Warhammer, Atlas, Madcat - I could go on. They're harder to use, but much more fun (in my opinion, at least).
Of course, variants do have to be different to have any specific purpose, so some degree of specialization is natural. The Osiris with 2x ERLBL is specialist, but I can live with it - it serves a defined role as fast sniper that would otherwise go unfilled, and doesn't have enough tonnage for other armament without compromising its main purpose.
What bugs me more is the 2x PPC Osiris C. It's too close to the A, with twin heavy energy weapons. I'd prefer to see one of those PPCs replaced with an AC5 or something. Now
there's some diversity!