Basically what I'm asking is which is more important

100 Skills like Blade Mastered, Armorer Mastered, etc or 100 Attributes like 100 Strength or 100 Endurance, etc.

I'm asking because I'm trying to figure out which is more important to focus on. I also don't really want to go up to Level 50 but I also don't wanna get stuck at Level 10.

I would say skills because
1) skills essentially determine attributes with the multipliers on leveling up
2) the 1 or 2 point difference between 100 skill and 99 or 98 skill is a lot more significant than this difference in attributes. Getting blade from 99 to 100 gives you the forward power attack, getting strength from 99 to 100 lets you carry like 5 more pounds and maybe adds 1 point of damage to your strikes. But then again, if you focus on leveling up certain skills, then those attributes will get maxed out in the process as well

Skills, definately skills.

If you have 100 Blade and 50 Strength you do 85% of the weapon's base damage. With 50 Blade and 100 Strength you'd only do 59% of the weapon's base damage. If your skills are high you wil lalso get their perks (like the paralyzing forward power attack at 100 Blade, the ability to repair magic equipment at 50 Armorer, the ability to cast stronger spells for every 25 ponts in magi skills, etc), but attributes have no perks.

One way to look at it is to see if there's another way to get the same effects.

Skills perks usually don't have an equivalent from enchantments like attributes do. You can fortify an attribute directly e.g. Fortify Intelligence, or fortify the benefit it gives, e.g. Fortify Magicka. But there's no Fortify Power Attack, and Fortify Blade doesn't add any perks if it takes your skill level past 25/50/75/100. So getting the skill levels directly is more important than the attribute levels, as you can artificially boost those to compensate.

Skills I reckon.

Although many people have mentioned that attributes have no perks, in actuality they do, at least some of them. For example, with the Strength/Blade example, what would be more important, dealing the most damage, a situation which only applies in battle, or carrying the most loot? However, I'm still gonna go with skills for the 25/50/75/100 perks, as they are generally more useful.