Best data Class for storing stats.

Hello everyone, this is a bit more theoretical and discussion oriented than other questions. I will still try to make it "answerable" though. I am making a game where the player and ennemies are made up of a bunch of pieces that individually have stats. I am trying to figure out the best way to access, process and store these stats. Right now I work with a dictionary, but it is tedious. I think a Stat Class will be better, but I want to make it future proof. What would you guys use? How would you create that class? And would you recommend any article/guide?

Requirements:

• Easily access and process many datasets.

• Fast copy.

• Can save and load from harddrive (fast).

• Can process the entire data set (like average with another dataset or do calculations, probably through operator overload).

• Easily create an empty set.

I do not need sorting (no quicksort or anything like that).

Thank you for any help. I know this isn't as precise as suggested for Unity Answers, but it is extremely important to get right.