I loved Julian Gollops games back in the day so definitely need to check out phoenix point when I get a chance but the early reviews were a bit mixed.
Idk what people thought they would play. The game is better than Firaxis XCOM if you do not play it with XCOM mechanics in mind but Phoenix Point mechanics.
People complain
a) That there isn't tech progression, yet tech is more impressive than XCOM. You just need either steal it from factions or ally one. (there are 3).
That allows from the boot to play 3 different campaigns differently. XCOM is always railroading you to the end, on every aspect of the game no deviations no different options.
b) Options that aren't only aicraft, classes/subclasses weapons & armour but also how you win the game. Synedrion has mist repellent tech which pushed back the mist. Others have other techs, eg Anu embraces the mist though mutations. (yes your troops become less human some are even half squid).
c) Complain about difficulty, trying on their first campaign to play on hardest difficulty. The game is really hard for newcomers, even myself having played in BBs for over 70hours prior to release, on veteran mode (one up from easy) is pretty hard. AI is pretty great on adapting it's mutations based on what has to deal with in the area.
d) AI mutations and adaptability mechanics. Can write whole essay.
e) Multiple storylines depending who you ally and your campaign choices.
f) War between factions and against you, if you go against them.