Ok, say you are building a company for a, for the sake of argument, 15000 bv game using 3025 tech. How would you build? Would you tend towards a narrower band of unit bvs (with say nothing cheaper than a WLF or odd FS9) or is it worth it to bring a few STGs or LCTS so you can bring along some more expensive assaults?
(currently I am working with a fairly limited hangar, so general advice is more useful than specific units)
As in so many things, it's not what you have so much as how you use it that counts most in that kind of situation. Stingers and Locusts are in fact perfectly serviceable, survivable and can be the turning point of a match if used properly, but it's not easy to do.
The first rule of using bug mechs in larger formations, 3025 or otherwise, is that you have to stick to your formation. Simply put, one Wasp operating by itself is an annoyance. Four Wasps acting in concert have as much firepower in close as a Battlemaster, with greater mobility and greater ability to keep up a steady stream of fire to boot. So when you create a lance, your first priority should be to match units with a) roughly equivalent speeds, and b) roughly equivalent weapons brackets. This will allow you to move your mechs as a unit without having one mech constantly lagging behind, and it will allow every mech to fire with roughly the same modifiers at the same target in the same flank/rear/front firing arc. There are of course exceptions to this rule, such as the classic pairing of a Hunchback with three fire support mechs, but with light mechs, you really have to keep your mission pure. Pairing an Urbanmech with three Stingers isn't going to wave anyone off attacking the Stingers. All it will do is slow up the Stingers or dilute their combat effectiveness by never having the Urbie with them.
The second rule of using bug mechs in larger formations is to screen them effectively. A lot of people will simply advance their units across the board as fast as they can and, since the bug mechs typically move faster than anything else, simply write their bug mechs off as cannon fodder. This is foolish and wasteful: as in the above example, nobody would consider simply writing off a Battlemaster in an unsupported headlong charge, so why should you write off the four Wasps that can match it for firepower? Instead, the best defense against losing your bug mechs should be the armor of your larger mechs and/or wasting a lot of firepower on highly improbable shots. Put simply, most people focus their fire on the most attractive target, and they gauge attractiveness by how threatening something is and how easy it is to hit. By making people pay a lot of attention to your big mechs, you can make them ignore the bug mechs until it is too late. So hold them back at range. Dance them as a unit out of easy potshots. If you want, give your opponent 10's or 11's to hit to run his ammo and crank his heat scale up. But while you're doing that, move your larger mechs into position and bring them forward. Make him choose between taking dicey shots at the recon lance that's dancing way over on his left flank, striking at the armored fist of your battle lance that will hit him in two turns, or taking the worst of all possible worlds by splitting his fire.
The third rule of using bug mechs is that the phrase speed is life means something a whole lot different in larger formations than it does at the lance level. At the lance level, speed is life refers to the simple matter of picking a position and moving at a speed sufficient to keep from getting vaporized by fire from 2-3 mechs. At the company level, speed is life refers to the fact that bug mechs are the most mobile asset you have, which means you can hang them back farther on a flank and still bring them in to concentrate fire effectively in close. At the company level, concentration of fire is everything: by attacking by lance and focusing fire, you can often drop even the toughest mechs in 1-2 turns, and doing so decreases their ability shoot back at you, preserving your own unit in the process. All your effort should be focused on a) maximizing the amount of fire you can bring down on one mech's head in a turn, while b) minimizing your opponent's ability to do the same to you. Speed being life for bug mechs, you can make them look more out of position and less of a threat before snapping them 9 hexes inward to hit the mech that's anchoring a battle line 3 hexes away. If your 4/6 heavies are your jab, then think of the lance of Wasps as your left hook: coming wide, and it connects only if you foul up your opponent's ability to block or dodge by jabbing him enough.
As one of two side notes, these basic rules rely on two basic principles of larger formation fighting. The first, concentration of fire, has already been mentioned. The second is the principle of mutual support and reinforcing fire. If you string out your opponent's battle line and then hit one end, in 3025 especially, you have instantly accomplished a) and b) mentioned above: because the ranges are fairly short in 3025, by lengthening the battlefield, you often put one some of your opponent's mechs out of effective support range of their other mechs. If one side of the battle line can't support the other end, they can't shoot back at you, can't concentrate their fire and can't prevent you from taking down one of their mechs through concentration of your own fire.
The second side note is that the change from L1 3025 tech to L2 3050 tech doesn't change the rules, only the implementation. As ranges increase, you can lengthen your own battle line and still mutually support the other side. On the other hand, as speeds increase, it becomes easier to bring in those light elements from further out to strike at your target.