The concern is not the user experience of developers. As you point out, that's a small crowd with little market significance. But sandboxing cripples, besides

The concern is not the user experience of developers. As you point out, that's a small crowd with little market significance. But sandboxing cripples, besides our ideals and personal experience, the apps we make. Users (of powerful, hard-to-sandbox apps) will suffer from this. Those users far outnumber the developers, and have great market significance.