How would you make a Battlefront Game?

Hmm. Designing would depend on what's required of the game, based on the info collected by the data analysist, & what product manager/producer/s wanted me to include.

Not another SWBF - tries to cram too much content which cannot be maintained/stored/evenly distributed. Instead, I'd make four to six era locked games which focus on the planetary based combat aspects of Swbf. One portion of swbf... Just as Squadrons focused on the space flight aspect of swbf & only expanded from there. (I'd really like to see a  map/battle/event/match/game that includes the mudtroopers.)

If the games had to be canon (with the exception that outcomes of battles can be non canonical) I'd recount the actual battles that occurred in any observable Star Wars material. Then start from there to determine which maps & characters will be made available for which games.

Battle Map based events on a schedule would be tailored to suit the material they're based off of.  (Not every battle would have named hero characters. There wouldn't be any heroes in there - unless heroes were specifically in that battle in media. There wouldn't be any air support if there hadn't been any written into the original narrative. This means that for some maps we'd have specific Droid characters/Jedi characters. Only available to play in certain battles.)

Different battles might have varying objectives... (The time would be affected by the main server/s - not by induvial console/device times)

Instead of lobbies occurring freely/whenever, I'd take the Ewok event approach. So players could learn to schedule for (a certain) battle they want to ""ship out"" on. It provides a bit of role playing for a person, to set a time and date of when they're going to be involved in a (simulated) battle. The schedule would have to be frequent though - to enable a larger portion of the fans participation.

I'd consider which features could be included to make the game a unique experience beyond it's STAR WARS theme. (Playing different games can help inspire me which features I could consider including. But ultimately, I'd have to consider which features are more popular among other gamers... It would help if I'm personally able to understand these features though. ) 

Concerning content & progression; maybe during some events, you have the opportunity to find a higher ranking position on the field.
(You could scavenge the armor on the battlefield for a chance to wear that rank for a while. Drawing ties from the Solo movie, as I was thrilled when this exact thing was implied to have happened for one of the characters...)
Although you could scavenge ranked armor, there'd be a progression bar so that if you're unlucky, you can naturally earn the rank - it'd be optional too. If you prefer to run around as a storm trooper, you can, the longer you remain specifically a Storm Trooper the more unlocks of battle damage you obtain for that rank. That way, if you want to express your fondness for the trooper, but still indicate that you are an experienced player, you can apply different damage textures you've unlocked through your battles. ((None of that clunky overhead UI pink and blue text with numbers &/or badges.)) Your direct character model would indicate who & what you are/ what you've accomplished. 
Credits could unlock prosthetics & other outward appearances. Your history would reflect this per character. Characters would align to maps. So you could edit your character for (battle of Blank) but whether or not you can immediately play that mode is dependent on event/map status.  

Over time, weapons could diminish.  If you pick up someone else's blaster on the field, & its pretty tattered, you wont have it for long. You'd have your primary weapon which you have all the time, & you'd have a secondary weapon which you picked up at some point - or bought with credits prior to the battle. Weapon skins would apply only if you have that gun unlocked, if you find a weapon on the ground & use that; it's previous users' paint job remains. Weapons would be the only thing that don't include battle damage skins - as they'd indicate their usability based on visible damage (unlike armor). So if you find a really neat discarded gun that appears to have damage paint - its not just a skin to look cool - it's actually damaged and will eventually explode/stop working. 

Maybe the armor could behave that way too but that might get too tedious. (I'd have to determine it based on data...) 

You'd have the option to put your grenades on a specific hand - also, you could use a blaster/s on either your left / right / or left&right, depending on your preference/s (it's always bothered me that they didn't have this in swbf15, you could change your camera angle, but never your gun hand... In 'Gears you could wall swap which hand your pistol was in, & I really enjoyed that...)  It's kind of universal. Not everyone is right/left handed, it'd be great for players to display their prefs in that regard. )