I think the key pinch was when Blim's Deo-A check, Ho-Oh, couldn't switch in because SR was up and both of his SR removers weren't healthy to be able to take a hit from Deo-A to clear the hazard. With all the voltturning, Fireburn could easily bring in Deo-A and start taking kills to destroy Blim's broken defensive core.
Blim was playing very reactively for the majority of the game. He had to respond to the VoltTurn and to the threat of SR. He was pretty much screwed when Fireburn called the Mega Gengar switch in with Judgment instead of Defogging. That was a game winning decision, along with the followup 50/50, (although he should have wisped before Defogging) as Blim lost his opportunity to remove Fireburn's best check to Kyogre and Ho-Oh which would have allowed him to apply pressure himself. If Fireburn had Defogged, Blim wouldn't have had to predict the rest as Taunt + Dbond = dead Arceus. Basically, Fireurn had to win two 50/50s (three cause he defogged first like an idiot smh) to save his Arceus and likely the game, which he did so props.
Also, defensive Landorus speed creeping Blim's Dialga gave Fireburn one of his only chances to SR after the Leftovers reveal and thus put Blim in the above pinch. Although, he could have also sacked Landorus to SR up against Ho-Oh (Phys def Ho-Oh can tank an uninvested SE so blim could afford to stay in and attaack) and then bring in Zekrom and keep the pressure on the SR removers going, he'd have to do a 50/50 between Bolt Striking the healthy Ho-Oh and Volt Switching out of Defog Grassy, though.
I think Blim had the team matchup advantage because he just had to remove either Landorus-T or Water Arceus with Mega Gengar (which he even had Shadow Ball on to fuck U-Turn Landorus, enough to pressure with the rest of his team) which is easier to do than for Fireburn to keep those mons alive. However, Blim's Ho-Oh team was too reactivish (like just about all Ho-Oh teams) to handle the situation where Fireburn outplayed his Mega Gengar, which admittedly was forced to do his job early with some risk instead of waiting for the opportunity of a sure kill (like Blim forcing Fireburn to kill a mon or Defog to clear up multiple hazards pestering his voltturn) because, again, Ho-Oh teams are mostly reactive and was going to be torn up by SR + pressure if Blim didn't act quickly.
If it wasn't obvious, I liked Fireburn's team a lot better than Blim's. Although, I'm wondering why Fireburn opted for defensive Landorus instead of an offensive, max speed Eplate variant to put more pressure on Ho-Oh and, more importantly, Specs Kyogre which Fireburn can struggle against otherwise. I didn't calc any spreads but I'm assuming his phys def Waterarceus (just guessing, not like the spdef will let it beat Specs Kyogre and scarf is amply covered with just max HP and Sylveon) and Espeed Deo-A + offensive pressure would have been enough to handle Mega Blaziken without the max defensive investment. (and zekky can't put up with the offensive pressure plus the prediction it would have to make to get around ground/fairy + mega scizor) Eplate EQs would also make up for using U-Turn over Toxic in pressuring Defog Arceus formes.
Anyways, gg guys. I enjoyed the replay. :p