Everything old is new again. Sounds a lot like certain sects of Christianity. They say you need to accept Jesus to go to heaven, otherwise you go to hell, for all eternity. But what about all the people who had no opportunity to even learn who Jesus is? “Oh, they get a pass”, the evangelists say when confronted with this obvious injustice. So then aren’t you condemning entire countries and cultures to hell by spreading “the word”?
Both are ridiculous.
I think it helps to think of browsing as a basic form of searching. Everything you can do in a browsing context, you can by definition do in a searching context…if the client doesn’t suck. The information needed to browse is embedded in the tags.
So this strikes me as entirely dependent on your client software. A good client should let you browse by tags. You could add Dewey numbers as tags to start with, so you can browse that way if you want, then add any other tags that might be useful (like genres, for example) on top of that.
The only difference with tags in this context is that books will appear in multiple places.