Think about it in OW4 we are probabaly going to be seeing: Meetles and Mugs, the queens, MudFlubs, Slig towers or slig tosses, Life cycles in the characters, Game speak unlike anything we seen before, Sligs climbing up ladders to get to you, An unexpected challenging gameplay, Maybe even the Sea Rex, Sligs smoking, possably vending bombs, Khanzumers, Chroniclers possably, Possible return to Rupture Farms, Recycling Machines that actually have the status board saying pretty crazy stuff like when you throw a slig in it would say 20% Fat 5% protean 1%usable.

And of course there will be new things aswell.
I alweys loved that old quicktime movie of MO when the slig came down the ladder and started smoking. Abe snuck up behind him picked him and brought him over to the recycle machine and threw him in.
Thats all I can think of at the moment if anything else do tell!