Considering that Punk had a whole host of superstars lined up who could easily hold the title, Punk's reign is more impressive (No bias). Bruno had jobbers, Backlund was too advanced for his competition and Hogan had a lot of stains to wash out of his shirts.
I don't think Punk is the longest reigning champ per defenses. It was common knowledge for me growing up that Bruno was the longest reigning champ in the WWE, WWF, WWWF.
Now to back up someones point about Hogan defending his championship constantly I can testify to that. I grew up in the bay area Oakland SF area and was at tons of AWA then WWF events. Every house show with the exception of about 3 That Hogan did not main event, he defended the title and won. I saw him defend the title off the top of my head live against names such as:
King Kong Bundy
Big John Studd
Dr D David Shultz (I believe Hulk was champ during that match)
So Hogan defended the sh*t out of his first 4 year run as champ.
I would think he has defended the title more compared to the 4000 days so i would say yes. Seen as there are no records dating back to then involving title defenses we will never know.
To the OP you mean who had the most title defences in one reign. Just because he fought more, doesn't make it longer, technically. Yes, if you spread each defence out to the longest period (whichever champion had the lowest defences per week). Unfortunately, I wouldn't say live events really count as they are usually just there to gauge new feuds/test things for upcoming main shows.