You can drop it at any point withhin range and shoot it to any other point withhin range. What do you miss there? The arrow indicating where you ordered it to shoot at?
Shard of the endless avalanche does exactly what you propose it should be reworked to if you put it in the spellmasterys slot. You might want to reread some of the other tooltips either. About eye of the storm: You are stacking crit like crazy thus making eye of the storm much more less effective. Is there a crit% you do…
Your skills still do controll or debuff. If you did not want to fokus oh higher damage (yours or your groups depending on the path) you should not have chosen tempest mage as your paragon path.