Season 17!?! I can't even remember what this game was like then, although hindsight always tells you it was better. But also, it WAS better.
Right now you have big strides in anti-cheat which are immediately washed away by the ongoing flood of secondaries.
You now have a speed-based meta which some people think is game-breaking. Play one match as Axle and you'll see. Or better yet, play one match of Wildcard NOT as Axle or Octane. Yeah, try that.
Oh, right. You've never played Wildcard. Don't. It was barely fun in its first season. Now it's a hot mess. See above.
Weapon arsenals came. And now are so hobbled as to completely defeat the purpose for which they were created.
There was a loot devaluation at the beginning of this season. You might not notice, but if you'd played the last few seasons then you would for sure.
You used to be able to craft a banner at a replicator, but they've thinned the replicators to the point where you're lucky if there are a half dozen on the map. By late circles you're lucky if there's one. And if it's one that's dropped in then it had better be on the ground when your teammate goes down because they're definitely not waiting for it to fall.
Evo harvesters will probably also be new to you. Again, there are a lot fewer of them now than there used to be, but you've been gone long enough that you won't care. Doesn't matter - the cool kids all shoot their way to a better shield. I've had kids on the mic ask me to stop picking up the harvesters because they want their shield to be "legit."
Ranked play continues to swing wildly between rewarding fighting and rewarding placement. Couldn't tell you which cycle we're in right now. Don't care.
I'm sure there are a million other things I'm forgetting, but you'll find out for yourself soon enough. You poor **bleep**.
Best of luck!