Yes, Jericho is getting up there in age. But IMO, there's no other wrestler on the planet like him. He can take the silliest of ideas and get it over with the crowd. His egotistical wrestling personality works well as both a heel and a face, although I prefer him as a heel. And he is always on the cutting edge of new ideas to make things fresh. And even though any gimmick he may be using would still be very over with the crowd, he's not afraid to change things up to stay fresh. His in-ring abilities are not what they used to be, but he's still a very good wrestler. Once AEW signed Jericho, they were legit.
When I was a kid, it was still an unknown that wrestling was scripted. Of all people, my grandma introduced me to wrestling in the late 70's! Heels were hated, and often received death threats. As a kid, I hated them as well. I fell for it. I hated guys like Roddy Piper and Ric Flair. Then over time and as I got a little older, I started cheering for them. I thought heels were more entertaining. I remember Chris Jericho in the WCW when he was often battling cruiserweight faces like Dean Malenko, Chris Benoit, Rey Mysterio, Billy Kidman, etc. Jericho was a very talented, even high-flying wrestler. He would throw tantrums and whined, and was absolutely hilarious. And then he made the famous Y2J jump to the WWF/E, and was an instant hit. Not only was he a top wrestler in his WWF/E time, he came up with many ideas that are still used. For example, the "Money in the Bank" contract was Jericho's idea.
As you can tell, I'm a Jerichoholic. I had lost touch with wrestling for a while, but then my 2 boys got into it about 4-5 years ago, and brought me back. I was excited when Jericho had his last run in the WWE with the "List of Jericho" because I was able to share it with my boys.
So, I'm excited for AEW and very willing to give it a shot. Mostly because Jericho legitimized it for me.
PS - I wish I still had my "WCW Monday Night Jericho" t-shirt!