User blog comment:Elphrihaim/Clarivoyance...?/@comment-1985493-20130806173415/@comment-5955640-20130807044656

I don't like taking exhaust for supports when it's a bad idea to be that close. Like I used to have Exhaust on Nami but I found that the general distance I needed to be to apply my spells was too far away to use exhaust. So I actually changed to ghost because I max Q or E. Thus close the gap my carry with spells instead of the summoner spell in and of itself.

I consider exhaust better for dueling or have low chasing power. Nunu with exhaust makes sense. You hit them with the Q to keep them in place. You exhaust them and now you ult them so they can't burst you down and can barely escape the AOE.