I hate it.
Not that I usually buy many Pandas, anyway, but I'm going to boycott the 2015, as well as any subsequent years or countries which follow suit. Even if that means I end up missing out on some potential numismatic profit down the road. (Besides, plenty of other things to buy for that, instead.)
Others may view that as a nice play, and gobble them up. And with enough people doing that, all of a sudden they become not-so-rare, after all.
True, there are plenty of old coins that don't list either weight or composition on them -- but those were issued as currency to be used as such.
The 2015 Pandas certainly don't fall under that category.
I think it's a stupid move for them. If they wanted to do this for a non-Panda line, to sell alongside regular Pandas, that would be different.
But they're not getting my money because of this. Like I said, plenty of other pieces to buy, instead.