If you choose the "Distract" mode of Stone Drake's second ability and the target is illegal when the ability tries to resolve, it won't resolve and none of its effects will happen
Two damage isnt too bad in Commander, so the benefits definitely outweigh the damage
There are plenty of other low-cost cards which can replace Wooded Foothills in this example, not just other lands like Krosan Verge (obviously better if youre also playing white), but spells like Natures Lore or creatures like Wood Elves
An example of the feature mode in previous games would be the Planechase and Archenemy game modes, although neither of these will be in the 2015 addition instead, players are being treated to a fully customisable deck creator, but Ill come back to that shortly
There are 14 MTG cards with Dredge these are the top 30 most-played
Three-mana 1/3s just aren't going to cut it, especially in a world of actual Bolts