Once Stampede Rider's ability has given it +1/+1, it won't lose that bonus if you no longer control a creature with power 4 or greater later in the turn
Sure, but its all about finding the right creature to sacrifice, Gravecrawler perhaps
I loved I honestly wasn't trying to make it more powerful, but I did
The Mimeoplasm becomes a copy of one of those, and gains +1/+1 counters on it equal to the power of the other
Divination reads that During your turn, whenever you draw a card, you may move 1 damage counter from chosen character to chosen opposing character, which in itself is a powerful opportunity to decrease damage, and either on the card itself or on others, and equally place this on other characters, rather than having to use up your opportunity to quest to do so, is powerful
And that something is a mechanic that the game would later on call 'goading', forcing one of your opponent's creatures to attack