Full Disclosure: I believe the BR spread should be changed to ±1 (as in you either see 1 tier above OR 1 tier below). However, that is not currently the case so I will suggest where the equipment should fall in the current system. However, should the ±1 be implemented, then I think Sidearms should have tiers.
Current ±2 System
Sidearm slot: doesn’t matter, since Tier 1 will see Tier 3 and I don’t think any pistols rise to Tier 4
Backpack slot:
Tier 1: Small Backpack
Tier 2: Small ammo pouch
Tier 3: Large backpack, small grenade pouch
Tier 4: Large ammo pouch, large grenade pouch
Mine slot:
Tier 1: TNT Charge
Tier 2: AT Mine
Tier 4: AP Mine
Grenade slot:
Tier 1: Smoke, Frag
Tier 2: Explosion Pack, Molotov
Tier 4: Impact grenade, White Phosphorous
Proposed ±1 System
Sidearm slot:
Tier 1: Revolvers
Tier 2: Current 1-2 Star pistols outside of revolvers
Tier 3: 3+ Star pistols/autopistols
With the current lack of tiers for all gear other than Primary/Secondary, Tier 1 can have people running 9 man squads with x3 Impacts and AP mines. This seeks to insulate the early tiers from that type of gameplay.
It also gives a reason to run something other than best pistols, large ammo/grenade/AP mine at lower tiers → with no mines available or explosion packs at Tier 1, people will be encouraged to use TNT & the tier 1 AT rifles (which has a side effect of letting the Tier 1 tanks be able to push more aggressively). The flame tanks being tier 1 might be an issue, but could argue they should be Tier 2 in a ±1 system or maybe AT mines get dropped to tier 1.
The ±1 system would also give players a reason to bring revolvers as it would mean you could stay Tier 1 and only see Tier 2 at worst.