It was the period from about July to October 2015 where people discovered how good it was to stack Damage Up with the E-Litres and Luna Blasters. Other blasters benefited as well, of course, but the Luna Blaster's disgusting splash damage and blast radius meant that it could easily kill you in a single hit with very little aim on the part of the user. The E-Litre's damage scaled in such a way that it didn't need a full charge to inflict 100 damage, so stacking damage up meant you could charge about 60% and still get someone.
And this isn't even the sub weapons: the E-Litre benefited from Damage Up, and its sub weapons, Burst Bombs, benefited as well. The obvious design intention of the E-Litre was to have it be an extreme long range weapon at the cost of close or medium range survivability. Thing is, if you stack enough Damage Up, Burst Bombs are suddenly this amazing weapon which does 40-50 damage with an indirect hit and 70-80 with a direct hit. This meant, even if someone got close to you, you could just start panicking and throwing burst bombs at your feet while jumping around randomly and the sheer stupid amounts of damage it dealt would give you a fighting chance against dedicated close-quarters weapons like the Sploosh-O-Matic, if not the upper hand. Burst bombs also had a stupidly high knockback value, which increased with damage, so you could fling a burst bomb at a tower and knock someone off if you didn't kill them.
Combine that with the E-Litre's impressive turf coverage ability (due to its range) and the special Echolocator, one of the strongest in the game, and you had a weapon that had no real weaknesses. Just from stacking damage. A few days ago I was playing ranked and using a suction bomb rush to break a rainmaker shield, and while I was throwing bombs at it about to pop it, an E-Litre shot the shield. Thanks to that weapon's damage modifier on rainmaker shields, it did enough damage to completely reverse what I had done and swing the shield around to the enemy colour slightly. And this is AFTER the weapon has been consistently nerfed in almost every patch since launch.
The Luna Blaster benefited too, since the vanilla model used ink mines and had an inkzooka. Ink mines had their lethal range increased from damage up, and the inkzooka is a seriously powerful special weapon. Tower control was a joke during this stage in the game's meta, since it was just this clusterfuck of Lunas slapping themself onto the tower and laying mines. Occasionally there would be a muffled KTHOOM and somebody would blow up because an E-Litre had shot them from half the map away.
All this is to say that, from what I saw in solo ranked, there was very little reason to use anything that wasn't:
So all the matches degenerated into the same thing over and over. It's like the FOX ONLY, NO ITEMS, FINAL DESTINATION meme from Smash Bros, except it was actually true. If the game hadn't received any balance patches, I think everybody would've burnt out on it much more quickly. The game was a broken mess where only a handful of weapons (which ignored most of the game's unique movement mechanics and instead focused entirely on killing people) were worth using.