If you're thinking of post count, a crawl of the BHQ site (basically downloading and parsing page HTML dumps) turned up the highest threads (approximate post count over 2k, page count, start date and thread title):
>6k 384 Apr 3, 2021 kevin walters
>4k 225 Aug 24, 2012 sack griffin new coach discussion
>4k 217 Sep 11, 2018 2019 broncos line up
>4k 202 Jul 27, 2013 official anthony milford to broncos
>3k 182 Feb 14, 2017 2018 nrl side
>3k 166 Mar 13, 2013 the wayne bennett super thread
>2k 97 May 27, 2022 payne haas
>2k 93 Aug 24, 2020 next broncos coach
>2k 86 Mar 8, 2014 broncos 2015 discussion
>2k 86 Jul 10, 2010 greg inglis signing thread
>2k 85 Jun 27, 2020 anthony seibold discussion
>2k 84 Feb 3, 2012 player movements and rumours 2012
>2k 138 Apr 13, 2013 official barba to broncos
>2k 128 Oct 26, 2009 player movements rumours 2010
>2k 127 Nov 27, 2013 official milford signs with broncos
>2k 123 Jan 20, 2017 our new halfback should be
>2k 111 May 26, 2022 payne haas retracts immediate release from broncos then
>2k 108 Oct 1, 2023 2024 pre season discussion pre season premiers
>2k 108 Jul 25, 2020 where to from here lets plan for 2021 er 2025
>2k 102 Sep 17, 2016 2017 line up
(exact post counts take rather longer to get).
As you can see, far and away the dominant topic was KW's tenure; the 2023 GF "only" went for over 1k posts. Bringing up the initial post of this thread (by theshed), pretty much indicates the same arguments were circulating then as they would still be over three years later:
I’m definitely not saying Kev should be on the chopping block yet, this was always going to take time and a lot of things are out of his control. But I have not been impressed with many of the things that are in his control. I want Kev to succeed as much as anyone, from a team perspective and because I like the guy, but early signs of not being up to the task are showing in my opinion. Maybe he will find his feet but I think he needs help and I think the club should throw barrels of cash at Bellamy or Bennett to come on in some form.
... and then concluded:
I hope Kev learns from all this and gets the hang of NRL coaching. Being successful under Kev would be a fairytale but I see a coach who is already out of his depth.