It's easy to get compared to other armours. I thought the Nuka world power armour would be better, but they aren't. I did all that work. Retaking all the parks, collecting the star cores and taking out all the raider bosses. Just to get power armour that's weaker than XO-2.
You just have to fight some enclave soldiers or do one quest to get a full suit of XO-2 at the highest armour upgrade.
Definitely needs to be harder to get, you don't even have to finish echoes of the past and can have a full set as long as you have an empty frame