A GPX can contain Routes, Tracks, Waypoints and probably some other data that I've forgotten about, though.
You're evidently uploading Routes. Try creating Tracks instead (if you're using an online tool that only creates Routes, find a better one, or at least some sort of conversion tool). There might be some differences in how the eTrex behaves when following a track (on the 30, you lose notification that you're coming up to a turn, gain some little icons about summits, and it won't auto-route using the map, but you still get a blue line to follow and the compass display does its thing).
The auto-routing routepoint limit makes sense, in as much that there's only going to be so much memory for the routing algorithm to use (and a hard limit below which a route will definitely work is more useful than "as many as you want, but use too many for a given location and it'll die with a stack overflow"), but if it's just doing point-to-point I don't see how that's any different from following a track, which makes the limit seem daft.
