Although I'm confident the New Outlook was released to us way before it was ready for public consumption, I'm happy to see constant improvements. I have a large mailbox. With the old Outlook, I had reached a point that the software frequently became unresponsive, especially when working remotely, i.e., from home.
I hated the reduced feature set in the New Outlook, but to give credit where's it due, many of those features seem to be slowly coming back. They are not always where I expect to find them, the program certainly looks different, but I'm beginning to find my way around.
The most important improvement I've seen is speed. Early on I began to slip back to the old Outlook to do certain functions. More recently I've forced myself to only use the New Outlook, although I'm managing six different email accounts.
Overall, I accept the New Outlook is a better solution for me when working from the Office, and especially when working from home. YMMV