As best I can tell, the asterisk being there is a typo; there used to be a note that E fares only earned miles "ˆ Effective June 1, 2012".

The note note about 2012 is irrelevant at that point -- we're long past the point of being able to claim flights from 2012 for mileage credit, right? -- and as best I can tell it's just that when they updated the page, they forgot to remove the asterisk.

I've flown both W and E fares, and earned miles on both as expected (I've also seen some AA codeshares on CX Premium Economy, but oddly I've only seen that for flights terminating in HKG, not for continuing flights, and the fares were around $300 higher R/T than the same fare on CX's own site.)

FWIW, I'm a big fan of the CX PEY product, although the update to JL's looks even nicer. Tip: the front row of each cabin has an actual legrest, and is the place to go as long as you don't mind losing the under-seat storage.