As I said, the problem with the Expansion Pass is that it was announced at the Game Awards on its own.
In the case of Smash and Xenoblade, the DLCs were announced in a dedicated Direct among other stuff about the games. It felt more like those were announced to tell the audience that those games will get supported after their release. Also, I don't think Xenoblade had any Day-1 DLCs so it doesn't feel as scummy as FE Engage's pass.
I actually remember that the Botw EP received a lot of backlash upon its announcement, and that was also something that was announced on its own, though it was also the first time Zelda received any kind of DLC and that was another thing that made people uneasy.
And finally like
@DecoReturns said, FE's prior history whit DLCs doesn't evoke much confidence that the pass will be a good deal.
Overall it's not the worst thing ever but it is definitely an announcement that was made at the wrong place.