Exclusive Weapons (EW) debut this season - one per troop type (Kimberly, DVA, Tesla), each unlocked through its own Battle Pass. Getting your main carry hero to EW Level 20 is the single biggest power jump available this season, well above what any other upgrade path offers.
Pick ONE troop type to focus first - whichever your main carry uses - rather than spreading shards thin across all three. The Kimberly pass tends to open earliest, so many alliances rally around it first, but there's no wrong choice as long as it matches your actual squad composition.
Around Week 4, Builder Alliance mode also unlocks - an irreversible, alliance-wide choice that swaps City warfare for facility construction. It's worth a real conversation with your alliance before anyone switches, since there's no undoing it once the whole alliance commits.