The big advantage we MEP s/holders get, beyond the expected SP uplift, is exposure to the whole HPA process. I know there has been lots of speculation as to what entitlement MEP has beyond supplying the feedstock but a scrip offer tidies this up (amongst other things).
But IMHO HPA is far enough in the future that it's unlikely to form a part of the valuation metrics for the bid and the market gives it zero value. Similarly for NNPL. Swings & roundabouts.
It will be interesting to read the reasons why the MEP board has chosen this route. I'm assuming it was an offer too good to refuse! And as you point out, there's always the possibilty of MEP2.0 for those wanting to maintain exposure to the base metal assets.
We'll see soon enough.
As an aside, it will be a shame to lose the civility of this board!