I do think that Nintendo should have spent a little more time and investment on advertsiment for FE:Warriors, that game deserved more attention for sure.
As for Echoes.... I don´t think they should have ported it right away for the Switch. That game wasn´t supposed to be a huge hit by any means, it was focused on core FE fans and still to be sort of a "test" of what future Fire Emblem games should have. I loved it, by the way.