This planeswalker can exile itself, too, which can protect it from a threatening board of attackers
Thornmantle Striker At 5 mana Thornmantle is costly, but its a two-for-one removal spell, and since you are running Elfball, mana is generally not an issue
If the creature you control does attack, and the creature you don't control can't block it for any reason (such as being tapped), then it doesn't block
however, they could always print something with so sick of a tap ability, or something with some sort of Stasis-like effect, or something else that makes our creatures all gain a powerful tap ability until end of turn
Note that you need this number of cards in addition to how many the game says you need to have leftover