Mayhem modes- I really think Gearbox could redesign it with models that they already have built in-- Anyways my two cents worth of ideas
Zerg Rush One of the most enjoyable things about Borderlands is that occasional feeling of being an absolute bada$$- So exploit that. Use Zerg rushes (large groups of lower level enemies that are easily defeated, but can overwhelm with sheer numbers and consume resources (Ammo) ) Make the player have to conserve ammo and use more tactics to deal with the sheer numbers and have enough left to fight the actual bad guys behind.
Bring the Rain Improve the AI- have it call for reinforcements (Like the cartel did) , try to flank the player, call in air support (Racks, jet pack troopers etc)
Fly Like an Eagle Low gravity areas would add a new dynamic, and allow SLAM to actually be useful
Storming the Castle Have more fortified areas, where cover becomes more important, make the player feel like they are assaulting an area not just running full tilt (NO FRIGGING MOVING ROCKS to jump on)
You Win or you Die Create alliances, example Maybe in no Mayhem when I assault the Maliwan base I am just Fighting Maliwan, but in Mayhem 2 or 3 now the COV have teamed up with Maliwan and now I have to change tactics to fight multiple enemies instead of them simply becoming bullet sponges (whose idea was that anyways, only one to profit would be that war profiteer Marcus…hmnnn Borderlands Conspiracy theory) This kind of change would change the tactics, have those bug things crawling out of the wall, COV screaming at you while Maliwan digs in, it would change the dynamics, with existing models. By Mayhem 6 you could be fighting the bugs, Maliwan, bots etc. Player would be more challenged and have to resort to cover, changing load-outs, conserving ammo etc.
Where is a dragon when you need it?, add auto turrets and defense systems to areas, one more already existing model that would lead to another challenge that does not need to be made from scratch (think Dahl turrets with repair drones,.
Constructor Revolution Bring back Constructors - In previous BL games these guys could be a real challenge with the right backup
RoboNinja’s The big baddy from TPS has found an abandoned Hyperion Facility and is cranking out Insecure Clingy Ninja Claptraps- Stealth capabilities, All of TPS’s ridiculous abilities for Claptrap etc. That’s right, you get another chance to shoot Claptrap in the face
Enter The Matrix Finally, Echocast recordings get interesting! Everyone wants to know more about characters, companies, monsters, Pandora etc… So, why not pick up that echocast say the one about Moze being in the trenches and suddenly YOU are sucked into the Echocast and fighting alongside a squad of Ironbears- You have to fight your way through the swamp and find yourself a way out of the Matrix- You could be the crazy from the train station traveling underground to fight the aliens with your fists etc… Basic stories are already there, could add more as time goes on. Maybe even give the player the chance to play as a psycho/Maliwan/Traunt/ etc
Anyways- My main point here, I think you could have Mayhem without reinventing the wheel or making everything a bullet soaked slog fest that has you contemplating duct taping the trigger button on your controller to give your finger a break-
What I expected personally from Mayhem was added challenges, not four year old nitrous huffing psyco toddlers throwing out ideas like bullet sponges, you have a big fat head and “the floor is lava”- Use existing proven models rather than investing in creating new ones, it saves resources, saves Gearbox money and gives us new tiers of difficulties.