+1 For the most part. I think it could be a great quest in 2021 with some updates/tweaks.
I agree about the deep blue shell. I think it should be looked at. It takes a long time to get there and finding it can be confusing, especially for new players.
Changing the pokemon reward could be more updated to make it more appealing. For example the kanto rewards tier 2-4 are Mime Jr, Munchlax, Abra, Shellder. Almost all players will skip these. Happiny is tier 1 which is nice, but unfortunately is no longer a possible reward once your doctor rank increases.
As another example Johto has Pichu, Togepi, Bonsly and Mantyke for tier 2-4.
Maybe some pokemon like Togepi and Munchlax would have been desirable a few years ago, but in 2021 they are not really relevant enough to be desirable rewards. I think a small update like this would make the quest appealing again.