I think the gauntlet match had many storyline aspects and has set up future story's. The match hadn't got a reason, but it was still enriched with story.
1) John Cena- no longer big match john? Elimination chamber is a must win for Cena.
2) Seth proves what he said last week. He is Mr Monday night. Plus he gets payback over roman eliminating him in the Rumble.
3) Elias takes advantage of a exhausted Seth. This is exactly what he is gonna be doing at the chamber. He's the last mofo in the match after all.
4) Setting up a Miz and Balor feud. Mizterage heavily interfere in the match. This means the outnumbered Finn may need to call on he's good brothers for backup.
5) see how destructive Braun was? Imagine him in a elimination chamber. Absolute carnage.
All this under an umbrella of the WrestleMania main event at stake. Too bad its obvious Roman is fucking winning.
After watching the match, I saw someone else point this out and mention how this was perfect wrestling writing. We forget often that wrestling writing is supposed to take place around wrestling matches, and also that stuff like that gives the wrestlers themselves more to chew on so you get awesome motivation and action like you did today.
Sure, there was the "plant the seed of doubt" trope with Roman that never works (Now he's the underdog! Bet he won't win now do ya?) That they do every month, but Rollins pinning him is instant credibility. Especially if Roman Wins the title by pinning Super Lesnar, Rollins has had his number pretty consistently through the years, even ending his last coronation. When Rollins is announced as #1 contender we'll remember this, and not jobbing to Bray fucking Wyatt
John Cena is officially Hiroshi Tanahashi. He's still (kayfabe) great and resilient but he's getting up there in years, and Rollins could survive all of Cena's super offense because 100% of prime Rollins is better than 90% of old man Cena. (Though this whole "I may not have a Mania match" crap needs to stop)
As you say, Elias is number 6 in the chamber and picked the bones of a winded opponent who fought the top two dogs in the company for an hour. He could sneak a pin on Cena even if Cena's been battling Reigns and Strowman forever, in theory
Finn Balor got some shine and a built-in feud with Miz as you say, and Miz's shenanigans felt special and gave him some heat tonight but made you feel like Balor could get some payback if say, those two start 1 and 2 and the goons are out on the outside.
Then Braun killed dudes because YEAAAAHHHH WOOOOO!!!!
Add in stuff like getting us talking, making us tune in next week, making these guys feel much more individual, etc, and this was written almost perfectly. It was really good. And while it would have been better had they announced like the winner could kick a guy out of the Chamber (which Strowman would refuse to do, which would confuse modern day fans but still)