Ironically, the parallel between the two companies is kind of interesting.
Days of Ruin was the final installment of the Nintendo Wars franchise, and after that, Intelligent Systems focused on Mario & Luigi.
Dark Dawn was the last installment of Golden Sun, and after that, Camelot focused on Mario Tennis and Mario Golf.
Seems like when something doesn't work out, the solution was "let's just make Mario games".
Well, I think it had more do to with FE’s near death that they had to switch focus onto FE for the sake of it.
Although GS and AW’s run are so similar. Unless if you go by the whole “Wars” franchise and all of that jazz, AW and GS both began on the GBA, became hits, had a sequel soon after, went a little on a hiatus with AW at least having a game in 2005 while GS didn’t get anything until 8 years later, and both died on the DS with DD and DOR. Although Golden Sun died to due to a mediocre game, while Advance Wars could’ve lived on if it weren’t for FE’s failures.
However, unlike Advance Wars, Golden Sun has Isaac who was huge on the ballot and has a high chance of being playable, while no one is really sure who to push for an AW rep and thus didn’t give a lot of support.
Sad, but if Golden Sun can have Isaac, hopefully it opens the door for Advance Wars, they were both in similar positions after all. Plus it would be nice to get two more GBA characters.