Ward abilities of creatures your opponents control won't trigger as long as Nowhere to Run is on the battlefield
Legality depends on the tournament format -- Behemoth Sledge can be legal in some formats and banned or restricted in others
The modes are quite different from each other, too, but giving your whole team hexproof, while maybe slightly over the top as most spells only target a single creature, is a good bit better than just giving hexproof to one of them
For example, a 1/1 creature that enters the battlefield with two +1/+1 counters on it will cause the evolve ability of a 2/2 creature to trigger
Blind Obedience The extort is valuable for lifegain and drain decks, but Blind Obedience really mucks up everyones works, especially in Treasure-centric strategies
This means the opponent cannot block, and those creatures will die after attacking