No ordering within tiers

Dark Empire
Krayt's Sith Empire

Galactic Empire
Legacy-era Galactic Alliance

Galactic Alliance (second galactic civil war)
Vong

PT Republic
CIS
New Republic

Zakuul

Vitiate's Sith Empire

Old Republic (TOR)
Revan's Empire

Ragnos's Sith Empire

Unsure:

Bane-era militaries
Rataka