Who will be the next Wrestlemania showstopper?

Gargano vs Cole at takeover was the only WWE produced 5.5 star rated match.... ever....

of course you could say it's very biased because wwe/f on got a handful of high rated matches compared to other companies.

And NxT has 3 - 5 star matches compared to WWE's (post name change) 1... ever... although WWF has 4

but if you look at the wrestlers involved it is telling.
Nxt Takeover New Orleans had the ladder match with Cole, EC3, Dain, Sullivan, Ricochet, and the Velveteen Dream.
It also had Gargano vs Ciampa.
NxT Takeover Philadelphia had Cien Almas vs Gargano.

until those matches the last 5 star was in 2011 - Money in the Bank CM Punk vs John Cena.

But match style and production is a big part. Because if you count wrestlers that are in WWE now.
the 5 star list includes
WALTER vs Zack Sabre Jr. at PWG All Star Weekend in 2017
Keith Lee vs Donovan Dijak PWG Battle of Los Angeles 2017
KUSHIDA vs Will Ospreay NJPW Best of Super Juniors 2017
Hiroshi Tanahashi vs Shinsuke Nakamura NJPW G1 Climax 2015
Shinsuke Nakamura vs Kota Ibushi NJPW Wrestle Kingdom 9 2015
Kenta Kobashi vs Samoa Joe ROH in 2005
AJ Styles vs Christopher Daniels vs Samoa Joe triple threat TNA Unbreakable 2005
Samoa Joe vs CM Punk ROH 2004
Rey Misterio Jr vs Juventud Guerrera ECW 1996

So, out of that whole list the 5 star and above club is
Adam Cole
Johnny Gargano
EC3
Killian Dane
Lars Sullivan
Ricochet
The Velveteen Dream
Tommaso Ciampa
WALTER
Keith Lee
KUSHIDA
Shinsuke Nakamura
John Cena
AJ Styles
Samoa Joe
Rey Mysterio

Now, if you just look more recent - say last 3 years 2017-2019 and giving consistently good matches - 4 star and above
The most consistent high level wrestlers for the past 3 years who are currently in WWE
top 11 -
Tied 8th
Adam Cole, Dean Ambrose, Samoa Joe and Tommaso Ciampa (8 high rated matches)
7th
Matt Riddle (9 high rated matches)
6th
Aleister Black (10 high rated matches)
5th
Seth Rollins (11 high rated matches)
4th
Johnny Gargano (13 high rated matches)
3rd
AJ Styles (14 high rated matches)
2nd
KUSHIDA (16 high rated matches)
1st
Ricochet (21 high rated matches)

so, in the end i'd say Ricochet... because he's close to averaging a 4 star match or higher once a month or every PPV.