I can see lots of reasons to distinguish between labour and capital. A big part of me thinks it would be appropriate to reward productive labour by reducing tax

I can see lots of reasons to distinguish between labour and capital. A big part of me thinks it would be appropriate to reward productive labour by reducing taxes and to discourage rent seeking by increasing taxes on investment income. There are practical reasons, of course, not to do this as we would rapidly chase investment from our country, but it is definitely worth thinking about these things.