ABA2 has the BetterPods plugin already integrated.

Here's what it does:

1 - Increases enemy squad size scaling with forcelevel (=time elapsed during campaign). There are 4 squad size tiers:
-- First tier is vanilla squad size +1 with an occasional +2 here and there. Minimum Podsize is four. (Forcelevel 1-5)
-- Second tier is global +2 squad size (Forcelevel 6-11)
-- Third tier adds the occasional +3 squad size. (Forcelevel 12-17)
-- Final tier is a global +3 squad size (Forcelevel 18-20)

1.5 - In addition to the squad size scaling, there are these adjustments to enemy squad balancing:
-- Facility Sabotage: These missions now have an additional Advent pod.
-- Facility Sabotage: The boss pod on these missions gets an extra +1 size and +2 forcelevel.

2 - Introduces the enemies specific to A Better ADVENT to various notable encounters:
-- Gatecrasher: Trooper pod now has a Drone. Captain pod now has a Riot Control, but only one Trooper. Bonus pod is now always a Sectoid Soldier and a Gunslinger. This is true for ALL difficulties!
-- Blacksite: The pod with a MEC and Troopers that guards the vial will now spawn with an AutoDoc and random Trooper variants.
-- PsiGate: The Codex and Gatekeeper guards can be replaced by random Codex and Gatekeeper variants.
-- PsiGate: This mission now always has a Chryssalid Queen and a Chryssalid King (in seperate pods).
-- Forge: You will now always run into the Advent Prime Sectopod.
-- Forge: The Sectopod Prime spawns with random MEC variants. On lower difficulties, the MECs are replaced by random Trooper variants. On easy, the Sectopod Prime spawns on its own.
-- Broadcast: All Archons, MECs and Gatekeepers can randomly be replaced by any of their variants.
-- Leviathan: No increases to pod sizes, but many enemies have been swapped for ABA versions. You will encounter a LOT of Primes in this mission. Be prepared.

3 - Several mission types gain variants that indroduce new pod settings, changing the feel of the mission
-- VIP Extraction: Can take place in a city that has recently been purged by the aliens. That town is now inhabited by nothing but Zombies, Puppeteers and Gatekeepers ... and XCOM is tasked to get the VIP out of there!
- Supply Raids: In the late endgame (forcelevel 19+), Supply Raids on Advent facilities can turn out to be raids on the local MEC Bay. These missions have many, many robotic enemies, from Captains that have only MEC followers to Sectopods. There is always a Sectopod Prime on these as well.
- Retaliations: There's a chance for retaliation missions in the midgame to turn into a situation with only few enemy pods, but lots of civilians around... this should make you suspicious.
- "Secure The UFO" missions no longer spawn Advent enemies, all pods are completely filled with actual aliens instead. Only exception is the very early game when no aliens are yet available as followers.

4 - Chryssalid enemies outside of the PsiGate mission are replaced by ABA Chryssalid variants appropriate to current force level. This includes Terror missions and the Infestation Dark Event.

5 - Retaliation missions have one to three extra civilians (one in early game, three in late game, two during the bulk of the game) to make up for the added difficulty.

6 - Rulers can no longer spawn during Council missions or during Avenger Defense.