SwiftUI

Wholesale adoption of SwiftUI to rewrite large, long-lived applications introduces significant business risk. Incremental migration strategies focusing only on the view layer while preserving UIKit navigation are recommended but require more planning than big-bang rewrites.

SwiftUI's preview system and dependency-heavy build graph often double or triple compile times compared to other frameworks. Large Swift packages sometimes require clean builds, significantly slowing iteration and delaying feature releases.

Multiple reproducible bugs in SwiftUI persist across beta releases, indicating that stability and performance remain unaddressed top priorities. Developers encounter recurring issues that block reliable deployment of SwiftUI-based apps.

The Preview feature in SwiftUI requires building the entire project and fails with compatibility errors when UIKit is present in the codebase. This prevents developers from using Previews to speed up development in mixed UIKit/SwiftUI projects.

SwiftUI requires minimum OS versions (iOS 13+, macOS 10.15+, tvOS 13+, watchOS 6+) and many features only work on newer versions (e.g., TextInput focus on iOS 15+). Projects supporting older OS versions cannot use SwiftUI or must maintain UIKit fallbacks.

SwiftUI lacks a natural, straightforward mechanism for creating reusable design systems. Developers must choose between adding modifiers to every component, creating artificial extensions, or scattering style constants throughout the codebase—none of which are clean solutions.