The new `FromRequestParts` derive macro cuts down on repetitive code. Instead of listing `Urls`, `StaticFiles`, and `RouteName` in every handler signature, you can bundle them into one struct. Small quality of life improvement that really adds up.

Session stores are now pluggable, so you can switch between backends without touching your code. Use in-memory for development, Redis for production, or the new database-backed store, which is now the default since it's good enough until you need Redis performance.

Forms are much more capable now. File uploads work out of the box just by using a pre-defined special type! Full chrono support means date and time pickers actually work properly, and you can configure HTML attributes programmatically with restrictions like "images only".

Error handling got a complete redesign. Before, you mostly got 404s and 500s; now you get proper HTTP status codes for different error types. The new system uses a single error handler instead of separate ones, and we managed to shrink error structs from 110+ bytes down to just 8 bytes.