Designing a rule set for a table top roleplay

[DAWNSTAR]

So, as the title says, I am designing a rule set for a table top roleplay from scratch. Problem is, I am worried that what I am designing is not appealing to players and I am unsure how to do certain things. For example, I have no idea how to determine armor. I have no idea how to factor in armor weight and weapon weight to carry weight. Should I be adding a specific equip weight instead of lumping armor and weapon in with it? Critical hits, how am I suppose to determine what classifies as a critical hit? Does a critical hit do three times as much damage or five times? Class abilities, I have no idea what they should be. Once again, I have never designed a rule set before so I am just looking for whatever information you guys can give. The link to the google document of what I have designed so far will be placed below. https://docs.google.com/document/d/1__g9zDN_nXsysl3hzIUBI0ZUpBAugrjbe4A4DAW8WgY/edit?usp=sharing

[Jerkchicken]

Well the biggest thing you need to do is to answer the questions of: What do you want out of the system? With that answered you get focus which helps in the process of making it. Also don't forget to work out your base math for stuff before you start adding stuff to it like crits. Secondly it seems like you're doing a D&D type setting which is cool and all. But my question is what does it offer or do differently from not only D&D but countless other derivatives