One of the goals of play is to minimise complexity and code boiler plate. When writing a library that other code will depend on, name spacing things carefully in packages that you know are going to be unique is very important. When writing a web application that you know no code is going to depend on, then long package names just become boiler plate bloat that you always have to deal with but never see the benefits of. So Plays philosophy is to keep things as short as possible, define conventions for where to put classes (eg models, controllers, views) and add default imports for example to templates for everything in these packages, and it's not afraid to break old conventions to do this.
If you want a great play experience, then I'd advise that you go with the flow and follow its conventions.