Well here's a question:
(I should note by now if you are here... you've already seen plenty of spoilers).
Would there be a motley collection of cast-off dothraki, unsullied, dragons, mercs in the east without Dany?
She decided to continue on with her small dothraki collection after Drogo died, she could have very well gone to Vaes Dothrak and become a crone.
She hatched the dragons... it may have been luck, but nonetheless she is the one who has them, and is the only one able to use them (afaik).
She has the unsullied. We should see more of them.
She even as a babe is a cause of fear and hope in the families of westeros.
It's not so much her skill or personality, its her lineage and inborn talent that make her a threat to westeros. Without her there is no Targaryen. Hence she should be a character that impacts the board when played.