I think the hunt that is most "worth it" would definitely be Deoxys, since it is easily obtainable and available to shiny hunt, and it's a Pokemon that is easy to obtain shiny, but I think when it comes to shiny hunts, worth isn't solely defined by hardly accessible hunts becoming easily accessible.
While a lot of shiny hunters, especially those that hunt in newer gens, may find the idea of a 1/8192 odds hunt unappealing, getting FRLG on the switch just to do a starter or legendary reset hunt or even a random encounter hunt may absolutely be appealing to some hunters. There may be some people that with these switch additions, simply want to get the game for the novelty of having a shiny they can call legitimate, or, some people might want the challenge of hunting in a game with lower odds if they haven't had access to it before. Some people might even want the game just to get their favorite monster in a different color with the cool sprite art, or one hunter may be stupid enough to for a low percent encounter, simply to say that someone did it and it exists.
There's a bunch of different reasons why a shiny hunter may deem getting the switch version as worth it. And in my opinion, if you're getting your experience and value's worth out of the game, then it absolutely is worth it to get.
