I thought he'd be replaced with Jack or something, in keeping with the current (Japanese) market. I do agree Rosie (or even James or Emily) might've been a good replacement for Percy.
It is strange how the normal Big Loader sets may have been discontinued despite their popularity (though I think the decision to license T&F instead of Bob the Builder was even more bizarre and a missed opportunity, but I digress). Now that one of the T&F sets is being re-released, the normal ones might be remade later, which would be even more awesome for your public layouts and for people who don't like the idea of engines in a construction themed toy (if not Thomas products in general).
It is strange how the normal Big Loader sets may have been discontinued despite their popularity (though I think the decision to license T&F instead of Bob the Builder was even more bizarre and a missed opportunity, but I digress). Now that one of the T&F sets is being re-released, the normal ones might be remade later, which would be even more awesome for your public layouts and for people who don't like the idea of engines in a construction themed toy (if not Thomas products in general).