In game ideas (Classes)

So i can't sleep. so i suggest to write down my ideas. I have thinking about my game classes. Ill creating mmorpg in post apocalypse. So i need create some classes witch will realistic, but like postnuke - so many guns. But how to make guns and melee weapons more or less equal (because i, like many mmo gamers, hate  ordinary shooters). I decline to make view form 3rd person, and enable play game with joystick. There no possibility to use cursor to navigate aim (on joystick). So idea is to use selector to select a target (select next target / select before target). So when u select target, hold fire button and dependent on your skill you will shoot to target more or less accuracy (miss -> head-shoot).

So why i start this post - i can't sleep while write down my ideas abut classes.
There is main classes:

1. Tank (miningunner/flamethrower)
2. Engineer (man who will use some engineering thinks to attack others)(robots, cars, cannons, mines, choppers...)
3. Trooper (just ordinary army guy)
4. Spy/Assassin (use light melee weapons, can hide, become invisible, climb on wall)

So after some time planing to add:

1. Medic
2. Sniper (use sniper rifles and hits targets from long distance)
3. Mystic (man who use telekinesis to attack enemy)