This is something I like a lot about the ending, it has a shit ton of potential for a sequel or continuation now that the worlds are one and Mina is still around.

Honestly Mina is pretty much done without magic powers. The potential with the sequel is that Star's actions led to the fusion of all dimensions not only Mewni, also everywhere, not only Echo Creek. She indirectly created a new super world, how is that going to work out?. So many possibilities