After looking through previous posts and not seeing anything of the sort, I thought I would suggest this.
The Gauntlet/Arena wouldn't be PvP like blast network and lockdown. It would be pure PvE. I have 2 variations of an idea, and 2 separate endings that would work for both.
The first version would be like your typical arena floor. You have a decently sized room, waves of monsters, and possibly some traps. The catch is that for every 5 waves, the difficulty will go up. I.e. 1-5 normal, 6-10 advanced, 11-15 elite. and after finished wave 15 the monsters move up a tier. This occurs until you reach wave 45 (for those of you bad at math that is when tier 3 elite would end) one of the 2 endings below occurs. The monster types can be completely randomized every day or so for different status effects. As for how the family type can be decided.... I'm still working on that. The loot from the monsters can come in a few different ways that I can think of. The first is that its like your typical arena, heat, crowns, and a chance of loot. The second is that instead of the previous, you would just get coins/loot/a chance of mats. The third is that they drop NOTHING and you just get the rewards at the end.
The second version would use the bosses (without their 2 "pre-boss" floors). This one has a few different ways it could be used. The first way is that you cycle through all 4 bosses on your chosen difficulty and get a chance to heal in between, or you can do it so that there is no chance to heal in between. Another way is that you cycle through all 4 bosses on the easiest difficulty, get to heal up, and then do all 4 again on the next difficulty up, and repeat.
The endings could be different for each version. The first one could have you get Crowns and rarities at the VERY END of the gauntlet. This means wave 45 on the first idea, and after boss 4 (for the type that you face all on one difficulty) or 16 (for where they progressively get harder) on the second.
The second ending could be split up for each wave like your typical arena floor. I.E. you finish a round, get rewards then continue/leave.
I'm thinking the catch to it to stop it from basically being an easy to get to arena, the player has 1 life. No sparks, No revives. This could stop people from just spamming 10 sparks to get the awards at the end, and again, make it more like an arena.
I'm trying to keep it as a side-grade to running the clockworks and not a straight up up/down-grade from clockwork runs.
Leave your feedback/ideas to add on below.
I agree with no sparks, but at least the ER should stay. you will make mistakes eventually.
make em drop nothing. so rewards are semi-controlled (ie, you get x boxes).
make it tier based, don't make it scale from 0. if you are t3, you will get rewards with no effort. that being said, rewards should be every 15th way.