Comment by ldesegur

Swift feels very immature in many areas. For example, Swift fails with generics out of most ordinary cases. Today, you still can't restrict protocol conformance (inheritance clause) to a type-constrained extension. That's a big issue with arrays. A struct wrapper is the go-to solution for many things where Swift generics break down and it's not the best or more elegant way to resolve its limitations. Many hopes for Swift 3.0 but I doubt they'll fix those.