I've been talking about the Mulberry Tree with some village mates, and I've come to a conclusion. The Mulberry Tree needs to be seriously nerfed.
It produces berrys earlier than any other tree, which would be a great trait. For any other tree.
It produces the most leaves of any tree, making it amazing for leaf wraps.
It's leaves can be used for Fodder, making it one of the most abundant sources of fodder (It's relatively trivial to collect several thousand leaves, and with it's 6 day growth time, can be advanced relatively quickly. Admittedly there's a lot of caps along the way... This is not my biggest complaint)
It produces berries on day 2, making it the fastest method of quality growth.
It's necessary for silk production, so it's an essential tree.
Ultimately it seems like there's very little reason to plant any other tree, and that in and of itself is a problem.
Sure Apples produce Apples and the nut trees produce nuts, but Mulberry is the King of Trees in general utility. The berry sprout time should be extended as a result to balance it's myriad of other positives.