You bet they did:
Season 2 CNS/ "The Finals Hacked" theme:
- New gamemodes:
Powershift (tug-of-war meets convoy on a moving platform) Terminal Attack (Search & Destroy, but it's hacking terminals instead)
- Sys$Horizon, new map, "unfinished/leaked" 80s style
- Hacking-themed gadgets such as the dematerializer and the gateway
- Weapons ofc (I don't remember which ones tho)
Season 3: Japan theme:
- We don't talk about ranked changes
- New game-mode: World Tour (similar to unranked tournament, but 8 teams total, win points progression and end-of-season multibuck rewards)
- Bow for light, dual blades for medium, winch claw for heavy
- Map: Kyoto 1568
Season 4: Sponsorships
- Reverted previous season's ranked changes
- New careers: sponsorships (choose which in-game sponsor to sign with, get prizes with their themes and compete on world tour to determine which sponsor wins the season) (yes, you can bet people started dissing each other for fun)
- Dual eagles for heavy, dmr for medium, shotgun for light
- Fortune Stadium: the best parts of previous maps, mashed into one and themed with the season sponsors' colors
Season 5: Time for la fiesta, it's the anniversary
- New map: Bernal, Mexico
- New gadgets: Black hole for lights, chain trap for heavy
- Shak-50 for heavy, some incendiary shotgun for medium
- Jukebox to relive all the OST from current and previous seasons
- 2 new sponsors, one returning
That's only what I remember from the top of my head, they added so much. Not to mention the copious amount of high quality cosmetics and the very forgiving monetization
The fun is still very much here, give it a try!