Hmm, random things I remember:
No cooldown on extinguishers/chem.
Pyra was new.
Spire was new.
Mercury breaking armor in one hit.
Loch heavy flak.
Squid flamethrower meta, heat-sink rounds being mandatory.
No matchmaker/Lobbies of Icarus.
The breif reign of the Lumberjack when it was released.
Banshee couldn't hit the broad side of a galleon.
Heavy clip being essential for light flak.