First, what "labels" button are you referring to? The button that is next to "Move to" and "More actions" is still there.
If you like seeing all your labels, then just mark all of them to "show" in settings.
Personally, I do like having the ability to hide labels that I don't use often. The only thing I miss as a part of this change is that we lost the "right-hand labels" lab. However, I suspect that this is just because of some behind the scenes change that the new labels system made, and they are working on updating it.
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-Nick