I cringe every time I read a post where someone comments how there's no incentive to play (in regards to multiplayer) once you've unlocked everything.
Anyone remember playing 24/7 De_Dust in 2001 for hours straight because it was fun? Katabatic (lol)? Facing Worlds? When did that stop?
I blame WoW. Blizzard trained players to expect constant participation rewards every 15 minutes as the 'point' to playing. As long as they can shovel busy work to get you chase that next title, transmog, achievement, etc the paint chip eaters will stay happy.
Multiplayer games don't need "progression". The interaction between players is the content. Today's generation of gamers are hopeless. Give them all a microphone and it's toxic town. Your opponents are no longer the players on the opposite team; it's your own teammates as everyone scrambles to blame each other for every death/loss.
When your game is designed around a shallow concept that doesn't provide enough incentive or payoff to keep players playing it, you need a carrot and a stick to make them play despite not really having the motivation to play for the sake of fun. I don't know how man times I've heard fellow World of Tanks players lament "I hate driving this fucking tank, this is not fun!" ... followed by...
"Why are you still playing this game then?" ....
"Because I need the next tank in the progression tree" ...
"I thought you have fun with the other tank" ...
"They released a new Tech Tree with new tanks, but the fun tank is locked behind all these not-fun tanks".
That's where the progression mechanics entered the realm of design. Those mechanics tied nicely into micro-transactions and monetization. You meter out your limited content because it is finite and basically shallow gratification that doesn't perpetuate very well. If you gave it all to them upfront, they'd get bored of it quickly and stop playing. Go play another game and lose interest in your game.
Tribes 1 only had nine weapons. 1 grenade. 1 mine, a beacon and a health kit. That's all you needed. Hundreds of hours of gameplay out of that. Nowadays, games advertise how they are better because of all the guns they offer, "30 model weapons to unlock", yet they're all designed around the basic fundamental traits of Tribes basic 9 weapons. They're just 8 shades white. This one shoots faster, this one hits a little harder, this one has more ammo... ect.
It's amusing to read the comment of "pride in accomplishment" and how triggered the community became, because it is so right and yet so wrong at the same time. Bullseye, you hit the central nerve right where it hurts most. Your game is about pecking a button in a virtual skinners box in the guise of a game and you just called out your players as the dumb pigeons trapped in the experiment that they are.
"Pride in Accomplishment" is a perfectly valid facet you should build into your game. That does matter and motivates players to keep coming back for more. However, where is the accomplishment in grinding shit out or paying to play the loot box lottery?
In tribes pride of accomplishment came from scoring a midair hit on your opponent, finally nailing the cap route to grab the flag, crashing the generator room in heavy armor. The day my n00b-self discovered that first you jump, then you jet to take off was a like discovering a super-power. Something that simple and dumb, like mastering the platform tutorial and feeling the
"ah-ha!" moment of figuring out how to work the jetpack felt like an accomplishment well beyond what gun I can use or what color of helmet I get to wear next because I paid money or ground out hours playing a mundane activity.
If you unlocked all the characters and "cards" in Battlefront II on day one.... what keeps you playing after a few days? I can't see it... it looks like a shallow "go no where, accomplish nothing" experience without the progression system. It just gets really repetitive and derivative quickly. Run forward, mash the button. Die. Respawn and repeat.