Here's an interview with the Takahashi Bros. from 2007:
http://www.nintendoworldreport.com/news/14626/takahashi-brothers-talk-golden-sun-sequel
This took place long before Dark Dawn became a thing. Here's a part that grabbed my interest:
"As a final thought on the topic, Hiroyuki was asked if he'd like to see a new Golden Sun game on a handheld or on a console. He said he'd like something that would combine both—"with the past and the future." But, alas, "that's just a thought." "
Lol, well Nintendo has released the Switch now, Hiroyuki. Do it!
Alas, I wonder how long it could take to make a new Golden Sun today. Mario Tennis Aces received quite a bit of free DLC before development on that game fully wrapped. How much resources from Camelot were taken from MTA DLC? Could Camelot have started planning their next game during DLC development for Mario Tennis Aces, the last bit of DLC having released mid last year (2019) with Dry Bowser, or after? Golden Sun returned to the limelight near the end of 2018 when Smash speculation was at its feverish. Time-wise, it would be most prime time to get Nintendo and Camelot's attention and potentially set plans into motion by the beginning of 2019 while we were sending those letters, and doing Golden Sundays. Assuming they didn't start on Mario Golf and/or whatever before then, it would bill a new Golden Sun game as most likely having started development in 2019, near that new trademark. That's assuming that Nintendo/Camelot weren't planning on returning to Golden Sun immediately after Mario Tennis Aces release, before this fandom found its voice again.
There's also the question of... remake or new game? The story of Golden Sun right now is very tied together. It ain't like Zelda, Final Fantasy, and the like with a fresh start every entry. A newbie can play Dark Dawn, but they'll be missing all the major references and story beats of the first two "Books" and the significance of Alex, the big flipping villain of this series that we still haven't gotten to fight yet. Don't worry though, Alex will be our Golden Sun rep in Smash, and we'll finally get to bop his head in with Mario or Isaac Mii fighter! :D
Anyway, for financial success, I think they'll need to bring everyone back to square one, and I only see that happening with either a remake/reboot, or a prequel of the age before alchemy was sealed away. A sequel to Dark Dawn would need to bring back Isaac and gang so we can figure out what the heck is going on with those Psynergy Vortexes and Mt. Aleph that DD teased us with and then left hanging for almost a decade now. A whole generation of new kids in the real world has grown up since then and wouldn't have a clue about anything that went on in Dark Dawn, much less the original two. I think we need to start from scratch. No info dumps, no bloated opening summaries. Back to square one, where we hear a strong storm rumbling outside and our mother is hurrying us out the house. We don't know what's going on, but we are immediately diving in!
I think remake/reboot, or a prequel with new characters is the way to go. For a prequel they could probably bring back the old djinn like Flint for fanservice.
The other challenge is that Camelot is pretty small. They supposedly spent a year developing the first Golden Sun on GBA (not counting the N64 plans that were in place first) according to this IGN import impression:
https://www.ign.com/articles/2001/08/08/import-impressions-golden-sun
Golden Sun: The Lost Age came out in less than a year after the original in Japan (OG: August 1, 2001/GS2: June 28, 2002). That's not accounting for localization where TLA saw a significant delay in North America until March of 2003 when it launched alongside the GBA SP. The original was released in NA on November of 2001. Dark Dawn had a near world wide release, and these days Nintendo really values that and would rather have the games be ready in most intended languages before hitting market anywhere.
Also, the specs of the Switch dwarfs the GBA, and Camelot has shown they like to push whatever hardware they've been on to a high degree, and that includes Mario Tennis Aces:
A big RPG like Golden Sun will likely require more resources than Mario Tennis Aces, that doesn't feature Camelot's popular RPG mode for these sports games. And Camelot doesn't do them for the console Mario sports games likely cause it would take them longer to finish the games.
Now granted, Xenoblade Chronicles 2 was outsourced heavily, and Monolithsoft had a small internal team actually work on that game using the engine from X. Gust's Atelier games are heavily outsourced with a company called Flight Unit creating things like the character models using Koei Tecmo's Warriors engine.
Outsourcing brings it's challenges though, and apparently Metroid Prime 4 ran into bottlenecks from too many different parts not synchronizing well with each other. And that's a problem a big Golden Sun game could run into, because the titles have incredibly intricate dungeons and maps that must work together because they feature puzzles that have required more than one map or room to solve. Golden Sun's maps aren't just mazes and open fields to run around in. They are vital to it's wholesome gameplay, and are part of what makes this series stand out. Now I'm no dev expert, but Golden Sun has a real strong Camelot feel from start to end, from the art direction, Shin Yamanouchi's character designs (been with Camelot since Shining Force III)
and substantial gameplay in every corner, with puzzle based dungeons, in-depth battle systems, mini games, etc. Outsourcing with Golden Sun and trying to keep that Camelot 'spirit' if you will, sounds like quite the task. Maybe they can partner with a big studio like Sakurai has with Smash. Perhaps Bamco again, with guys closely tied to the Tales of games, lol. Metroid Prime 4 was rumored to have been in lead development by a Bamco studio, and they have been involved in Nintendo's Arms title and are currently working with Sakurai on Smash.
But honestly, I don't know if they have the chops to make interesting puzzles to solve in a 3D environment. Camelot used 3D models for Dark Dawn, but that was still very much played as a 2D overhead game. Only Nintendo's own Zelda team has proven to have the chops for an ambitious 3D dungeon design that can use psynergy for puzzle solving. Triple A devs have their dungeon looking areas play very straight forward and are mostly mazes to navigate through.
Which draws another question. Should Golden Sun's next entry even be in 3D? Will the title get the resources and expertise needed to successfully accomplish a Golden Sun game in 3D? Or is looking for a suitable art direction for a higher end 2D RPG Camelot's best bet? The battles will be 3D of course, be it faked like the GBA titles or otherwise.
Anyway, I've rambled long enough. Basically, in summary here, I feel that a theoretical new Golden Sun game is still probably far off. It wasn't too long ago that we made some noise and the trademark was just last year. Unless development started long ago, it's sprite based 2D, and/or a ton of resources are going into it, a new Golden Sun will probably need more than two years to bake and I highly doubt Camelot's next game has had that kind of time in the oven at present. Granted, that doesn't mean an
announcement can't happen this year. The new Animal Crossing for Switch is finally getting ready to be released, and it was announced well over a year ago. I doubt we'll hear of a new Golden Sun in development in the manner in which we've heard of Metroid Prime 4 and Bayonetta 3 are in the works. I imagine an announcement will be accompanied by some footage, like Breath of the Wild had. Or better example, similar to the announcement of... Golden Sun DS:
I still remember that moment! I was so taken aback at what I think I heard Reggie just say. I couldn't believe it!!!