T-45 power armor

Since the release of 4 I’ve been puzzled by one thing, why is the armor is incredibly fragile compared to 3 and NV, was this for gameplay purposes or something else?

So I just had a thought. we see in fallout 4 and 76 that all power armors use a universal and interchangeable frame. This frame is powered by fusion cores, although it is stated that t-45 uses fusion power cells. My theory is what if as the power armor designs went on the core suit (the power armor frame) was upgraded as well, but the core design wasn't changed, allowing for the interchangeability of pieces seen in the later games.

Power Armor in Fallout has been portrayed as the pinnacle of personal protection with most wastelanders who can usually scavenging a suit they find a keeping it for their own use whether it's protecting them while they're out exploring, construction, or other combat related activities. The same goes for factions. All factions if they can make use of Power Armor to give them a better edge in fighting whatever it is they're fighting. The BoS and Enclave being primary examples. Now although Power Armor is extremely powerful, it is not unstoppable, nor does it make a faction unstoppable. Power Armor is just the tank of the Wasteland, and like the tank, is has a myriad of weaknesses.

Gauss Rifle: The Gauss Rifle for all intents and purposes is an extremely power Anti-Material Rifle with both energy and ballistic variants. This means the Gauss Rifle can rip through pretty much any material, including Power Armor. This means that if for example the BoS was attacking an enemy stronghold and the enemies happened to have at least two Gauss Rifles in good defensive positions with great lines of fire the BoS could suffer extensive casualties and also completely lose suits since the Gauss Rifles would damage them beyond repair.

Missile Launcher: Missile Launchers are great for taking out heavily armored positions or opponents. This also means that they are great for taking out Power Armored opponents, of course the Missile Launcher will only reliably knock out T-45 and Raider suits in one or two hits. T-51 and T-60 suits will be able to withstand more missile hits than those two suits, with the T-51 being able to withstand the most.

Mines: Mines of every kind, especially Pulse Mines, are effective against Power Armor. If the Mines are dug into the floor any opponent in Power Armor who steps on a mine their Power Armor will suffer extensive damage while the person inside might be wounded. The regular Frag Mine is the least deadly to Power Armor users unless they're in Raider or T-45 suits. T-51 and T-60 suits will be able to withstand the explosion and mostly protect their users. Pulse Mines will not directly harm the user but will instead incapacitate the suit itself, rendering it useless during the battle.

Nuke Mines are the most potent against Power Armor capable of doing extensive damage to anyone who is inside and completely ruining the suit. The Nuke Mine is a Mine armed with a small nuclear explosive that is as deadly as a Mini Nuke. The Nuke Mine has an advantage in that it is concealed and unlike the Mini Nuke, does not give it's targets a warning before detonating. On top of that the Nuke Mine when stepped on will immediately send it's payload straight into the foot of the suit of Power Armor and likely penetrate the boot and send the rest of the explosion inside the suit up the leg and into the torso. This will mean that the user will likely be killed immediately and the suit itself will be extensively and critically damage and might be damaged beyond repair. Nuke Mines can also be placed in a minefield with other Mines including both standard Frag Mines and Nuke Mines meaning that if a Nuke Mine is triggered it can detonate the entire minefield potentially grinding a Power Armor assault in it's tracks.

Fat Man: The Fat Man launcher is a weapon that launchers minature nuclear bombs. This of course translates into it being a weapon that can assuredly destroy whatever is in its field of fire, from civilian structures to fortified positions. Power Armor is also vulnerable to this weapon and any suit can easily be destroyed if directly hit by a warhead and critically damaged if in the AoE of the warhead's detonation.

Laser Weapons: Lasers are usually seen as being useless against Power Armor but better than ballistic weapons. While Lasers are mostly useless against Power Armor they still have the potential to penetrate Power Armor, as can be seen with Assaultron's Head Lasers which can easily put a large hole through the chestplate of any Power Armor.

Plasma Weapons: Plasma Weapons are also good contenders for anti-Power Armor usage but are not really a viable weapons. They will burn off most of the armor but unless a large amount of Plasma Weapons are used the Power Armor will emerged unscathed with only scorch marks over the armor.

Ambush: The ambush has for hundreds of years been useful in taking out larger and better armed opponents. This is best seen during the Second World War especially in Poland, the Balkans, and the Soviet Union when partisans would stage attacks against supply convoys that would have at least one tank or armored car in "trouble areas". The partisans would stage their ambush and usually knock the tank or car out before it could react. This would translate well into Power Armor. If a BoS patrol was moving through an area enemies could easily launch an ambush and potentially disable the Power Armor before it had a chance to counterattack making the rest of the patrol easy pickings and giving whoever attacked the patrol potentially a new suit of Power Armor.

In conclusion: Power Armor is a force multiplier, but not an unstoppable force multiplier. As I stated before Power Armor is now the Wasteland's tank and like the tank of the dead before it had a myriad of weaknesses and if an enemy is to combat any faction with an extensive Power Armor collection they must take advantage of those weaknesses or else they will be annihilated. But the primary reason why Power Armor is seen to be unstoppable is because more often than not, most hostiles in the Wasteland have mostly useless ballistic and some energy weaponry and those who do have the weapons that can be used effectively against Power Armor fail to do so, leading to those in Power Armor untouchable.

*THIS IS FROM A LORE VIEWPOINT, NOT A GAMEPLAY PERSPECTIVE, SO FORGET POWER ARMOR HP VALUES*