There are various OO modules that try to provide some of the convenience that Moose provides, while reducing the cost. For example Moo, Mo and M. Maybe one of them does what you want. Or search for terms like object and class.

That said your use of strict validation and construction in the same method makes it very hard to subclass from your classes. If that's not what you want, you might consider splitting up the two, and maybe provide an initialization methods that subclasses can call on an already blessed hash.