I'd say 2019 as a *year* absolutely excites me more overall, but summer 2020 slightly edges out summer 2019 for me in terms of individual seasons. Though, it's super close. I'm basically looking at it like this...
Avengers: End Game
Once Upon a Time in Hollywood
Godzilla: King of the Monsters
The Lion King
Spider-man: Far From Home
Ad Astra
... all of which will be fantastic, I'm sure, but only *one* is made by one of my favorite directors (Tarantino)...
vs.
Untitled Christopher Nolan Project
Dune
Top Gun: Maverick
Godzilla vs. Kong
... two of which are being made by *two* of my three of my favorite directors, Nolan and Villeneueve (Fincher being my all time favorite).
Don't get me wrong, I think summer 2019 will kick summer 2020's ass, box office wise. It definitely has more all around fire-power. But likely getting Nolan AND Villeneueve in the same summer would be rarified air (not to mention throwing Spielberg in the mix as well). Add the sequel to one of my all time favorite movies (Top Gun), which I'm hearing is turning out pretty great, and summer 2020 is just a bit more tailor-made to my personal tastes.