Sad to say this, but...
Battlefront 2015 is better built in terms of good mechanics, big maps, freedom of movement and infantry units are not as overpowered as Battlefront 2's reinforcements and heroes. Battlefront 2's potential was there but it was brought down by unnecessary requests, the pay-to-win fiasco, factions inbalances, etc.
The few issues with Battlefront's 2015 are the overpowered Chewbacca, and OP loadout, unlimited hero glitch, and a few game breaking and sequence breaking issues. You can tell the dev team spend more time creating this game. What about the TIE targeting computer sounds (soft lock) feature missing from Battlerfront 2?!
No Shocktroopers or Shadow troopers as reinforcements, and very few customizations for Empire and First Order which became immersion breaking at some point. If the fans can get it right with mods, why not the dev teams? I have been a huge supported of the movie only accurate stuff for any future Battlefront games, exclude cartoony features like those awful helmets worn by the ISB agent (should had been the black Imperial officer cover).
Also the faction inbalances, in Battlefront 2015 your chances of attacking and killing an enemy are varied depending on where you place your shot. I managed to kill a rebel infrantry guy with a single headshot from my E-11, while in Battlefront 2, it takes 2 shots, 3 or 4 for body which is an awful idea.
I can list down the hundreds, or even thousands of issues with Battlefront 2. As for the eras, I cared little if Clone Wars or Sequel Trilogy was there, was more in for the gameplay than the era shuffle.
Also, heroes don't need passive healing or health buffing abilities each time they kill an enemy. Battlefront 2015 only had the bacta grenade, which only gave heroes 30% health buff, not a 10% each kill.
Making heroes inconsequential to the battle also made Battlefront 2015 fun and gave those Star Wars vibes. The idea of locking heroes behind a BP standard at 4000 BP today was a terrible idea. Just because Joe Schumuck can't get a hero because he/she sucks at the game shouldn't be a standard to punishing players to assist those who can play offline or CO-OP. Carrying the weight of a team is frustrating.
My only reason to revisit the oldie, but goldie Battlefront 2015 is because it's a better designed game. Too bad it's getting shoved down the grave with EA not wanting to patch it for 4k or PS5. End of the rant...