Yep, we've considered building an iOS and Android version. But that means we need to make more money and hire more people. Our team is very small right now.
The new sync engine is written in Javascript, which is faster than Python, but the main performance improvements came from changing the architecture.
You could give the application away for free with a sub, while saying to Basic users they gotta pay for it.
The application Emby has the same model.
I think its fair. Me, I don't want more subs (and I'm not a business user so probably not your market). But I'm fine paying a (high) one time fee for an application.
The new sync engine is written in Javascript, which is faster than Python, but the main performance improvements came from changing the architecture.