Jericho is great. I'd rank him somewhere in the top 20 of my lifetime.
Guys I'd rank ahead off the top of my head. (Drawing power, as an attraction, great matches and mic skills combo)
Hogan
Warrior
Rock
Austin
Macho man
Bret Hart
Vader
Vince Mcmahon
Shawn Michael's
Triple H
Undertaker
Hall
Nash
Foley
Goldberg
Ted DiBiase
Sting
Lesnar
Ric Flair
Kurt Angle
Eddie Guerrero? (It's close Eddie with a better prime but Jericho with the longevity)
John Cena
Batista? (Again close)
Roman Reigns
After this list I'd add guys like Jericho, Daniel Bryan, Benoit, Owen hart , Rey Mysterio etc
If you just judge him by in ring work he could be top 5 or he could be top 15. Depends what you like