Then I would probably just buy the coach tickets and be done with it, although if you need elite status miles, that *might* be a justification for spending more on non-refundable B class tickets, and maybe some award upgrade seats will open up.

Have you checked at how much more Y class tickets are? Those would probably be fully refundable and have better odds for the upgrade, anyway. Then you could decide if it's worth the extra cost of the Y tickets with an upgrade vs. saving the money for your trip and sitting in Y (which really isn't all that bad across the pond, and KL intra-Europe "business" is nothing to write home about).