When the deck was still part Belcher, you could often pitch a Land Grant you didn't need any longer, but since the introduction of Beseech the Mirror, we don't run a lot of green cards, likely making these free green creatures a liability nowadays
Like Charizard and Venusaur, big man Blastoise comes with a certain fanfare
(2/1/2014) Unless some effect explicitly says otherwise, a creature that can't attack you can still attack a planeswalker you control.
At the same time, the market for such cards is very volatile
If you ask me, in my +10 years playing TCGs, there are usually three aspects that need to be true for a card to be good or, at least, one of them needs to happen