Those that have played competitive FPS may have recognized a trend: any weapon that can kill in a single shot gets very popular. In Counter-Strike for example, the only weapons that are used once a certain cash-threshold is passed are ones that can kill in one shot: the AWP sniper, the M4/AK, and the Desert Eagle (when you're a little poorer). Why are those weapons preferred to other, cheaper ones that might have a higher probability of killing someone, albeit over a longer period? Sniper rifles are rampant throughout a number of FPS games: Battlefield 3 and CoD being the most obvious ones, for much the same reasons. In Mechwarrior Online, dual Gauss cannons or stacks of medium lasers are the weapons of choice for the competitive arena. In EVE, the humble Alpha Maelstrom was king for a very long time.
It's simple maths really: ultimately, the way to ensure success in a fight is to receive the lowest amount of damage while killing as many enemies as possible. That means overall damage dealing potential isn't as important as being able to eliminate an opponent in a shorter time. In EVE, that was apparent with the Maelstrom fleets that proved so popular: looking at EFT or another fitting program, it is clear that the 1400mm Maelstrom has terrible DPS compared to, say, and Armageddon (which also costs about half the price and does more than twice the DPS). The fact that only 10 or so ships were enough to take out a BC in one volley was, however, very impressive. Before TiDi was introduced, Maelstroms also had the added benefits of working past lag and killing enemies before logistics could land reps. The only reason that Alpha fleets have disappeared is that they were pitted against ships they couldn't hit effectively (Zealots + Rokhs), meaning they effectively weren't alpha ships anymore.
In the land of Mechs
In MWO, the same pattern is visible. While 'disruptive' weapons that keep players from shooting (like multiple Autocannons or a constant barrage of LRM or SSRM) can be very effective, they just aren't up to par with as many Gauss cannons or as many lasers as possible. This is despite the fact that generally fitting more than one Gauss cannon requires serious sacrifices in armor/engine size/ammo due to the fitting requirements. Likewise, fitting 4+ medium lasers (or 5 large lasers, a personal favorite with the Cataphract 1-X) has a similar effect. While opponents are attempting to kill via disruption and require a lengthy time to kill (the crucial factor here), two or three well-placed volleys from 2 Gauss cannons or a number of lasers are likely enough to kill them. What happens when, like EVE, this destructive capability is multiplied? In theory, with 5 large lasers, players have an alpha strike of 45. With four mechs equipped in this fashion, and some decent aim, they could kill an Atlas (the most heavily armored mech in game) in a single volley.
Since there are no mech limitations in MWO (8 mans could go for 8 double gauss or 8 5xLL, though this may eventually change), it is easy to see how this would create an issue. Just like in EVE, MWO groups may run into the problem of having too much alpha and having to spread their damage out. That's a slightly ridiculous notion given that others using more conventional fitting will still require time to kill their alpha-wielding enemies, meanwhile losing an ally every 10 or so seconds. Now why should players be excited about the coming assault mech, the Stalker? It could in theory fit 6 Large Lasers, even possibly 6 Large Pulse Lasers (with decent cooling). This would give it an alpha strike between 56 and 60, enough to kill many mechs in one shot.
Needless to say, I'm very intrigued as to how PGI will manage to balance this issue out...