Aerith is great simply because she has a healing limit, and it usually comes in handy that it gets executed with priority. Give her some more heals and attack magic, and you have a character you can always use. Her other limits are great, too, yeah.

In the past, I've probably just assembled a party based on attack strength and disregarded the healing, but I also spent a lot of time grinding in the past. In my current playthrough, I've done almost no grinding, so having a healer is nice. I guess I'll have to rely on materia to do all of the healing when she dies.