There are a couple difficulties that come up with this.

1. The amount of time Nintendon't saves on loads isn't necessarily the same between runners. This came up as an issue in Sunburn speedruns recently where certain players ended up having much faster loads, even though everyone was playing on Nintendon't.
2. Nintendon't affects other things besides load times. In particular, it removes lag in certain areas of the game (try spamspraying in the village in Bianco 7 on Nintendon't, then on Wii, for instance), and it can cause abnormal behaviour in certain shines (Manta insta-death is Nintendon't exclusive).

These differences mean getting an accurate offset to add to the timer for a run on Nintendon't would be all but impossible.

Side-note, the discord has a channel (#lb-discussion) dedicated to this type of talk. Bringing it up there is probably your best bet to gauge community interest since SRC forums are not payed much attention usually.

@KuroKid64 This is an uninformed opinion. You are suggesting that top 3 in 16/120 is equivalent to cutting 1 minute off the current SMS WR, yet no one knowledgeable about the state of SMS any% is even entertaining the idea of 1:12 happening anytime soon. It is unheard of for anyone to play within less than 1:40 of their Sum of Best in Sunshine, yet even for Nindiddeh this wouldn't even bring him down to a 1:12.

Concerning RNG: SMS is not less optimized because the WR does not get perfect RNG. The standard for optimization has to take into account the rarity of such RNG. Compare with 64 for instance - the sum of Individual Level records put together in a 120 run would yield a 1:33:xx time. This is almost 5 minutes faster than the current WR, yet it is unreasonable to use this as evidence that the game is not optimized, because it is completely unrealistic for anyone to match all of these times in an RTA run.

Concerning Category length, again, the length of the run shouldn't have any bearing on our perception of how optimized it is. A shorter category just means that the theoretical difference between an ideal run and the RTA record is smaller in terms of absolute value. This is not the same as optimization!! For instance, certain Individual Levels are very close to being absolutely perfect (some frames off the TAS) but they're not more optimized than any%. In the context of the IL these frames are a massive timeloss!

You say yourself that the games are not comparable due to differences in mechanics as well as RNG. This is correct, but then why are you trying to make that comparison in the first place?

This post also feels disrespectful of top Sunshine any% players' efforts and skill level. You talk as if Sunshine runners were strictly inferior speedrunners to top 64 players, but you don't bring forward any arguments to defend this (hotly controversial!) point of view. You also don't acknowledge the overlap between the 2 games - Weegee, Fech, Gainai, Guy, JJ, Diddeh, Nanashi, Galapagos... plenty of players have found a lot of success in both games, which contradicts the idea that Sunshine players are just worse than 64 players.

I apologize if I come off as hostile, but I care a lot about SMS and my friends who're working hard to bring down the any% WR and it upsets me to see their achievements belittled.