Beth did the right thing with Power Armor (PA) this time around. It's so awesome how it acts like a mechanized suit of armor and that you can upgrade it. But we all know that the modding community can and will take it further, so lets discuss that here.

Fusion Cores

Requiring Fusion Cores (FC) was a great way to balance the use of PA, but they're so darned abundant that needing them basically becomes pointless. There definitely needs to be a reduction in the amount you can find. They need to be made not as common and even rare in vendor inventory. Also when selling them to vendors (which would be an odd choice if they are rare) they need to be bought and sold based on their charge percentage. It's crazy I can sell a FC at 1% charge and get the same value of one at 100% charge.

Power Armor AIA (Artificial Intelligence Assistance)

There's already a mod out that allows you to program your PA with AI and make it a sentry of sorts and that alone is pretty awesome, but lets take it a step further. Imagine having the ability to upgrade your suit with AI and set it to protect you or pretty much become a companion. You can still hop into it whenever needed too. Also being able to set it to be biometrically locked would be nice too, in other words YOU are the only person that can enter it. Meaning you can leave it without having to worry about popping in the FC and wasting precious time if under attack. Or what about if you equip it with a jet pack and can set it to come to you if you call it?

HUD Augmentation

Would also be nice if you could set up different HUD elements like Night Vision, Thermal Vision and Assisted Targeting.

Achilles' Tendon

For those of you who dont know this terminology, Achilles' Tendon is a reference to a Greek Mythology character known as Achilles. He was unstoppable in battle and unkillable. He had only one weakness, the tendon that goes from the back of your foot and up into your calf. He was killed when that one spot was pierced with a spear. The PA should have one such spot, the FC insertion area. Shooting that one spot should damage the FC and make it unstable and cause it to explode after a few seconds. This would be an awesome way to take out enemy PA but also work as a double edged sword to you if your ever so unlucky.

Fusion Cores are already a weak point in power armor, you can target them in VATS and everything. If they get too damaged, the user will be forced out and the core will explode. (it's really fun to get the penetrator perk, since then you don't have to turn them around to hit the core)

Not sure about the power cores being too abundant. For me the biggest limiting feature is the armor degradation and the need to keep it in good repair, which requires trips to power armor stations with lots of supplies. I think the fusion cores are abundant in order to allow them to actually be used for power hungry things like jet packs, or to be ejected like grenades with the nuclear physicist perk.

Or as ammo for the Gatling Laser. Maybe increasing the default consumption rate would be effective? That might make things like Jet Packs or VATS even worse, though.