I chose beast master as my subclass and am enjoying it, but I just have 2 pieces of feedback/suggestions:
1. Summoned beasts are super noisy!
I don't mind a little bit of grunting or growling (or chittering in the spider's case) but most of the creatures are very loud and constantly grumbling. The bear especially is a noisy fellow. My suggestion is maybe just toning it down a little bit, or making the noises more irregular.
2. No way to dismiss summoned beast without it dying in combat or long resting in camp
I don't actually play table-top D&D so forgive me if there's a mechanics reason for this not being an option, but I'd really love a way to dismiss summoned beasts. If you're in a tight space or doing finicky things, having the giant ass of a bear in your way is a little detrimental.
