People, this is not an alternative spelling of Ali. It's not the same word in Arabic. They derive from the same root and have similar but slightly different meanings. They are pronounced differently, hence the double A. Aali is pronounced with a long vowel, Ali is a short vowel. I don't know the exact difference in meaning, but I just wanted to let you all know - this is a different name. It's definitely not as common as Ali among Arabic speakers.
No no no no. No don't do this.. stick with Allie. It looks so much better and people won't spell it wrong EVER. So yeah don't do this to a perfectly fine name!
For Muslims, Ali is a name that carries a lot of religious significance. He was the son-in-law of Prophet Mohammad; Shi'a Muslims believe that he was the rightful successor of Mohammad, and Sunni Muslims consider him to be the fourth rightfully-guided caliph.
The word sublime in the definition makes me think of sour lemons. It must be a sign that this isn't a good name for babies, because people will say "Aali!" and all I can think of are those sour lemons. Gross.