It was just indeed about the pace, and always being that bit quicker than you'd expect from... everything about him.
You see his size, his shoulders, his stride length and the speed his hips and knees are moving, and he's about half a metre per second quicker than he's got any right to be.
Josh is properly quick as well, maybe not quite the top end of Tom, but I'm not sure that's just because he doesn't get to show it as often (or train for it).
As for Croft not doing the hard work, and just hanging out on the wing - that's 100% coach's orders. England and Leicester both had plenty of close in grunt work in the likes of Moody and Corry inside him, so wanted to use Croft that way to maximise his point of difference.
Generally though, I thought you guys might just like some feedback form someone who's been watched the vast majority of his club matches for the last 8 years. (eg, he IS a lineout option, he covers more than just 6 & 8)