1. If you don't ohko something, you need something else to hit. I often had to Tetra+UC at Count.
2. More AC is always welcome. Always.
3. Shockvibe is a waste.
Nothing is set in stone, if you don't like the order change it? It's not like I'm forcing you to pick anything. Basically "why learn anything else other than Tetra" is your mentality then fine.
I ask you, why learn Adrenaline when you have Pumping? You don't use Eagle all the freaking time holy hell. You only use it in PvP+Bossing.
I just find these points somewhat condescending and you don't need to ask something if it's your own character and you know enough to do whatever the hell you want with it.