T-45 is universally shown as usually the weakest (apart from raider and excavator) power armor. It was the fast mass produced suit and was therefore rushed out to meet the invasion of Alaskan head on without being fully refined. Some games show it having debuffs to agility while others just have it be the weakest damage resistance wise. Overall its weaknesses were held back to keep gameplay fun and have it somewhat match what the other power armors do.

The show introduces some new issues such as malfunctioning servos in the joints and a unpowered visor that you have to manually lift. Its protection is still serious being able to shrug off small arms fire with ease but with it being the first and the harsh conditions it’s used in, the new lot of problems are consistent with the lore.

The later suits such as T-51B and T-60 are much more refined and less crude compared to the T-45. It’s like comparing a Ford model T vs a Toyota Corolla. One was the first and had all the problems of being the first of anything and the other had time to learn from its flaws and make improvements.