which skill tree you guys think that is in fault in skyrim
like
unarmed........example useless but helps you reach lvl 100

I'm not sure I understand. Are you asking what skills could be included in the game in order to raise the level cap to 100?
I don't think we need a higher level cap. I've never reached level 81 as it is, nor do I think I'll ever do so.

Just getting lvl 100 like a good old rpg

The highest level you can get to I believe is 81, unless expansions changed all that. (I don't have DG or HF)

There's no need for more levels.