I think a factor in Morgan's decision about whether or not to leave after next year will be the development and performance of Napheesa Collier. By all accounts, their games are very similar. So you might expect Napheesa to be Morgan's heir apparent.
If Morgan thought she could contribute to Napheesa's development by staying another year, that might be an inducement to her to do so. Just as one of the reasons -- reportedly -- why Shea Ralph decided to stay for a fifth year was to help develop one Diana Taurasi.
On the other hand, if Napheesa plays up to her press releases to the point where UConn fans are thinking "Morgan who?", then that might be an inducement for Morgan to leave, so that she doesn't take minutes away from Napheesa.
However one chooses to look at it (particularly if "one" is Morgan), Napheesa's performance next year is likely to be a very significant factor.
But I think Geno will "recruit" her to stay (as he did with Kalana Greene) by pointing out how UConn is such a good life compared to the real world of the WNBA and the foreign winter play that awaits her afterwards. I think that will ultimately result in a decision by Morgan to stay.