One thing to consider for a day time Grand Final. Today, like many Sundays on the October long weekend over the last decade or two, will top 31 degree at around 2pm till 5.00 pm or so. As such you are asking the players to play a high paced game in very hot conditions.
I've been to enough GFs at Accor to know that with all the concrete, its even hotter than the air temperaturee inside the ground.
If you think I'm exageratting, watch the NRLW GF today. That game will be played during the literally hottest part of the day.
I'd suggest player welfare might be a factor to consider here, and not just "oh I came have a BBQ lunch and watch the footy if its a daytime GF". Not everything in the past was always better.
I've said this on the V'Landys thread and I'll say it again....(long post disclaimer)
Whilst the Grand Final is held during October long weekend, 3pm kickoffs are definitely off the table (with ONE exception, which I'll elaborate on in a moment).
I 100% agree with you that V'Landys et al. at the ARLC do have player welfare in mind, especially in a situation where you get a hot day under clear skies. Not just half the ground attendance sitting in the eastern grandstand - as well as the eastern parts of the northern/southern grandstands of Accor Stadium - but I observed earlier during the NRL state championship GF match that around 3pm, the shadow cast by the western grandstand was only just covering the metre markings on the western side of the field (e.g. 20, 30, 40, 50 etc). So, with a 3pm kickoff in clear skies (during the hottest time of the day), 3/4 of the playing surface is still baked in sunshine.
The best the fans can hope for during the next tv rights deal - commencing in 2028 - is the twilight Grand Final we had during 2008-12. Kickoff should be NO LATER than 5:15pm, although closer to 5:05pm would be more ideal (which is the equivalent of and would replicate the Sunday 4:05pm kickoff that occurs during the regular season when there's no daylight savings). With 5:15pm at the latest, you'd at least see approx. the first 70 minutes of the game being played before sunset, with full-time under twilight skies. Furthermore, as observed during the NRLW GF, at around 5pm, the shadow cast by the western grandstand extends to just past the sideline on the eastern side of the field. So, the whole field is in shadow by kickoff during 5-5:15pm.
Now, back to the one exception I mentioned earlier: during years when the Grand Final is held on September 30 (i.e. no daylight savings), sunset is still around 6pm. 2018 was the last time this occurred. Next time this occurs is in 2029. Those are the years where there's a very strong case for a 3-3:25pm kickoff. Full-time for the AFL Grand Final this year occurred around 5:20pm, so 35 minutes or so has proven to be more than enough post-game time to conduct interviews, presentation ceremony etc. Also, there isn't that mass of deadweight time Ch9 had in the past, where full-time for day Grand Finals occurred around 4:40pm (4:15pm during 1995/96, due to an earlier 2:40pm kickoff) and the final 30 minutes or so of the broadcast leading into the 6pm news bulletin was just Ken Sutcliffe waffling on with Fatty and Sterlo, trying to fill-in time.
So, my suggestion: with a closer to 3:25pm kickoff in 2029, most of the field will be covered in shadow by kickoff, fans still get their Grand Final during the day, and Ch9 (or whoever the FTA broadcaster is from 2028 onwards) gets that direct segue after post-match into 6pm news bulletin and retains their audience. 5:05-15pm kickoff during other years with daylight savings: fans still get to see footy played predominantly during daylight, the timeslot is family-friendly to those living in New Zealand and the eastern states of Australia, and the FTA broadcaster gets a sizeable portion of the game in prime-time (post-6pm). I would take this scenario any day of the week over a 7:30pm kickoff, which is way too late (on another unrelated issue, something else that desperately needs to be corrected is there's too long of a time lag between events on game day, especially between the NRLW and NRL Grand Final).
