I went with WWF, but it's close. I'll break them down year by year.
1989 edges out 1992 as my favorite WCW year. Flair was at the height of his powers feuding with Steamboat and Funk. Sting/Muta was the Rock/HHH of the day. Meaning you just KNEW these two were going to be huge in a year or two. Luger was great as a heel. Luger usually was great from about 87-90. Haters don't know what they're talking about. Face Midnight Express ruled. I loved the Skyscrapers and Varsity Club. GAB 89 is one of my favorite shows ever. Can't really think of any big missteps.
1990 was a big step down imo. Funk,Steamboat and Muta were gone, but we did get Arn and WIndham back to kinda sorta make up for it. The Flair/Sting feud was cool, but it would have been cooler if Sting didn't miss 5-6 months. That really hurt the momentum they built up in 89. Varsity Club broke up and the Skyscrapers downgraded. (the only time I'd EVER consider Taker replacing Sid a downgrade :lol) Luger did a good job as a face and the Midnights were heel again. Tbh, I lost interest at some point in the year, but the Black Scorpion brought me back. Too bad they botched it in the end.
1998 WWF was a promotion at the height of their powers. Raw was must see TV every week. I loved just about everything they did, and was super into the Austin/Vince, Taker/Kane, NAO/Funk & Foley, and Nation/DX feuds. Plus guys like Owen, Snow. D'Lo and Funk. 1998 Rock is simply the best. Even the B Shows were cool with all those Hardyz, Acolytes, Too Much, Brood, Kaientai matches. Val & The Godfather were fun midcard acts. Just a super fun time when wrestling was the coolest thing around.
Lots of people crap on 1999 WWF and they're right....in a way. Yeah, the booking often made no sense. It was wrestling at its Crash TVest. I can't even remember who was face and heel week by week when I look back on it now. But it was still must see TV. You never knew what was going to happen but you couldn't wait to see Raw so you could find out. Personal favorites like "Big Shot" Hardcore Holly and Kurt Angle broke out this year. And Mick Foley was the most likeable babyface EVER. Perhaps a purists nightmare, but I'm not stuffy purist.