http://software.opensuse.org/search is the only way to access packages without login.
There is no way to browse packages in repositories and read package and repository descriptions yet. Even installation of more packages using one-click install is not possible. Installing additional packages from just-added repository is very complicated as well.
I got a rough idea, how to get a web interface for it: Customize a web shop software: - "Category" would map to projects - "Item" would map to packages - "Add to basket" would add package to selection - "Checkout" would generate one-click-install file - "People who bought..." would map to recommend tags or use webshop statistics. - "Price" would map to download or package estimated size.
The only remaining categories to map somehow would be distribution and architecture.