Or instead, have this as his first ability: "As long as it's your turn, Gideon Blackblade is an X/X Human Soldier creature with indestructible that's still a planeswalker, where X is equal to the number of Plains you control." Or whatever template you want
Pushing your deck above 60 (or 40) cards makes it harder to find key cards, increases the risk of "mana flood" (drawing only lands, so you have nothing to cast) and "mana screw" (drawing too few lands, so you can't cast any of the spells in your hand), and makes it more likely that you'll draw unplayable hands
interruption or breakdown of web host
No one was warm and welcoming
Of course, these numbers assume that Base 1st Ed had a similar print run to Urzas Legacy, which may not be true
Furthermore, Iono will also likely be durable and heavily used in the Expanded format