is a dragon who is amazing at engaging a teamfight. If I as Aurelion Sol use my E Q combo to engage a teamfight from super far away I am almost garunteed to get a flash reaction out of an enemy. If that enemy doesn't flash then they will almost definitely die at high level play due to very fast coordination.
can do the most DPS for an AP champion from earlygame to midgame. That's where
takes over and does more DPS at high level play.
Because of the range of Sol's W he can make picks thanks to
which is a similar situation to the EQ engage in that he forces an enemy to flash or to use a movement based ability.
Sol's ultimate can be used to move the enemy frontline out of the way so it's safer to approach OR it can be used to secure a kill thanks to the speed of his ultimate being tremendous.
Most of Sol's weaknesses can be covered in a major of three ways. One of which is more viable.
Sol's major weaknesses are his high mana costs, his shortage of self-peel, his strength isn't very viable against champions with blinks who can bypass the danger of Sol's stars. Examples include
and 
In a teamfight Sol only has to worry about mana. Sol doesn't have to worry much about peel and if an enemy
blinks directly in to try and kill him as long as
is standing in the middle of his team then the
is going to be melted very fast.
In the Jungle, Sol grab himself blue buff. Not much explanation needed there. The EQ ganks are also very powerful as Sol can gank pre-6 very often.
The last way for
to cover his weaknesses would be to play support due to the mana regen Items being very good for Sol's mana pool. As long as the Sol grabs a
then he gains the same utility he would normally get. The difference being he'll do very little damage. So this is most definitely not an effective role for
to play as.
So yeah I would say there are a lot of reasons to pick
in the LCS