Ok I want to say a few things about this analysis, even though I'm not QC.
Overview:
- Remove the point about it being a good lead, because it's not really. The closest thing to a good lead would be Scarf Flygon, but again dedicated leads don't really exist, and even if they did, this isn't one.
- Only the defensive set counters Victini, and even then Glaciate exists (uncommon, but it's not the worst option on Mixtini) and CB can still do massive damage to Flygon
This post by Meru explains how Defog is Flygons biggest niche in UU, so I think it should be the first set.
Defog:
- Toxic should be mentioned on this set in moves, but I don't think it has the space for it on the set itself.
Band:
- You need to mention what Jolly let it outspeed and what Band lets it do. Give specific examples of what it can now outspeed and KO.
- IIRC calcs shouldn't really be in the analysis, and these calcs are pretty irrelevant.
- Usage tips needs to be expanded. Talk about removing immunities to it's STABs, or when to lock yourself into Outrage, or how you should go for U-turn early game.
Scarf:
- This is a minor GP thing, but put spaces between the slashes
- Put Hasty first, because the way you have it you act like Jolly should be run with Fire Blast and Hasty with Defog, which is wrong of course. Speaking of which, with the new drops I think Naive is better than Hasty.
- Again on that note, don't hype Fire Blast, it's weak and bad to be locked into coming off an uninvested 80 SpAtk.
- Make a set details mention of moving 4 SpAtk EVs to Defense when using Defog as well.
- I don't think you understand Usage Tips. We know it's an ok but outclassed revenge killer. Usage Tips is about when to switch in or what move to go for when, not "you don't lose much by running a Scarf"
- Just in general, expand Team Options.
Other Options:
- Put the mixed set here. (see below)
- Iron Tail is pretty bad, and it doesn't "counter Fairy types" any more than it helps out Hydreigon
Check and Counters:
- A lot of things can be added, you even completely neglected revenge killers.
I would remove the mixed set entirely as it is now outclassed by a lot more Pokemon, especially the drops.
Also, you forgot to move Other Options and Checks and Counters to the bottom where it should be.
I know this seems like a lot, but I hope I helped.