I would absolutely 100% suggest migrating to EA 15 explicitly for the stereotype handling.
Some people will find the fact that you can't type in stereotypes inconvenient. They will get used to it. More importantly they will actually know what stereotype you are applying.
The properties window will now display fully qualified stereotype names and all stereotypes applied. Where the point above helps to avoid making mistakes, this helps you to identify mistakes that have already been made.
Stereotype properties (and unstructured tagged values) are the biggest UI change related to stereotypes. Tagged values from a profile are fully integrated into the properties window. If you're using a lot of unstructured tagged values your team may get upset. They lose the dedicated window, being relegated into a page within the properties window. It's a big win if you're using a profile, a small loss if you're not.