Just to be clear, I'm not talking as if all those would headline the same year. I would just make a point about any of those headlining full stop only happens if the festival had a huge downgrade, that's my opinion.
Also it's time to get The Prodigy out of the old, reliable and retuning, Download have had 3 years to get them, they are even having an act in as sub bumping over then who were booked to headline before from the get go. Biffy Clyro can join too.
Foo Fighters aren't going to headline Download and Green Day firstly don't open the door to them and secondly they didn't need anyone to open the door lol. Dave has played it, he know if he wants it or not. Green Day have also not opened the door to NIN or Nickelback, not even remotely a resemblance.
Your Legacy Bump Up section is just a bit silly. Suggesting at least one of those to get the bump up is the same as saying ADTR should have headlined Slam Dunk 10 years ago but they didn't so why would it be a good suggestion. KSE and LOG shouldn't be in any of these list. No big shows, no legacy, just returning 3rd down acts that get booked to top 20k events, not even 40k, let alone 60/70k. This is where we let what we would like overshadow what we should get and they should book. LOG did Wembley Arena once 1hr 15 minutes and a bunch of smaller academies, KSE not even that.
Hypothetically speaking, but realistically too, any of those two much weaker bookings don't look good headliner bookings with any combinations of the strong one's in my opinion. That's not to say they are solid bookings elsewhere but not at the top. KSE shouldn't even get to sub.
Justice live in Paris on Amazon Prime tomorrow evening (well, certainly in the UK at least):
https://www.amazon.co.uk/gp/video/detail/B0D5NDBTYC/ref=atv_hm_hom_c_fgrWYT_21_2?jic=8|EgNhbGw%3D