Golden rule: Gimmicks Will Get You Killed. Doubly, trebly so on Ironman. Jeff Goldblum said something about being so caught up in 'could' that you never ask if you 'should'.|
The passive attributes of the ghost armour are actually its main strength - the solid HP increase and the game-leading +20 defence. As you go up in difficulty the aliens deal more and more damage, and so it becomes less about weathering hits and more about never being hit at all, and the ghost armour is top of the tree in that respect. So use it as medium armour with extreme mobility and a nice gadget and you won't do wrong.
Grapple is lovely and (map dependent) can be better than flight.
Ghosting itself will guarantee you the drop on aliens when it is used. I've never seen a grenade thrown 'speculatively' or based on remembering there was someone in the area. Doesn't mean you can't get caught in an explosion and exposed, but the enemy will always go for someone they can see - it's one of your major advantages over the AI.
So, if your forward sweep encounters a pocket of mutons it offers an alternative to falling back and drawing them into an overwatch trap.
LB, you really are a massive geek.