I don't know the full details behind it, but they're working on changes to the type system in GDScript. IIRC they said the biggest issue they hear about with th

I don't know the full details behind it, but they're working on changes to the type system in GDScript. IIRC they said the biggest issue they hear about with the current system are that it's optional, which means that the compiler doesn't really do any optimizations based on knowing types ahead of time. In the future, there will be a setting to enforce static typing throughout a project, allowing the compiler to perform better optimizations because it knows that the type of a variable will never change.