So there has been a large debate going on on the official Battlefront 2 forums on whether or not Cross-Era Heroes should be a thing that makes it into the full game.
For those of you who don't know, Cross-Era Heroes means having things like Darth Vader leading the Separatist Droid Army against the Galactic Republic being lead by Finn.
The primary argument in favor of Cross-Era Heroes in all modes is it will allow people to upgrade and progress their favorite heroes no matter what era they're playing. These people argue if a player has become proficient with Darth Maul, that player should be able to use Maul regardless of what era they're playing in. Basically these people say Fun > Canon.
The primary argument against Cross-Era Heroes in all modes is it won't look or feel authentic. These people argue that having Darth Vader lead the Separatists goes completely against who Vader is, and it just would look goofy. From what I've gathered most of these people are in favor of having Cross-Era Heroes in hero focused game modes.
The way I see it, only a few heroes should be able to cross eras with no changes to how they play. This would be examined on a hero-by-hero basis. If a character is different enough across multiple eras (Obi-Wan, Anakin/Vader), they should be two separate hero characters.
Let the debate commence!