If you somehow can't discard a card (probably because you had no cards in hand and another effect prevented you from drawing cards), you won't put any counters on Cait no matter whether or not the defending player discarded a card or what that card's mana value is
I've come round to it mostly because of the push that Daretti originally gave to encourage artifacts, which was then followed up with Pia and Whirler
It wont ever go back to the way it once was, and thems the ropes
One of these Planeswalkers, however, is quite a bit different from the others
Playing lands, casting and tapping their creatures and artifacts these are the bread and butter of Magic
One thing we've seen happen in the past is that when a popular supplemental product comes out shortly after a Standard set, the Standard set is sometimes forgotten and under-opened as everyone spends their money on the supplemental product