Suddenly your 4/4 is a 6/6 that gives all of your permanents hexproof - which is absurd on its own - and then also puts two +1/+1 counters on each of your creatures at the beginning of combat on your turn
If you have the life to spare, Sylvan Library is ready to become a Necropotence proxy
To show how efficient this card is for the right deck, the final versions of Miracle Grow, which were dubbed Super Grow, used Mystic Enforcer as a finisher, since by the time you'd get around to casting it you had an all but guaranteed 6/6 flyer for four mana
So, add some haste to your deck today
This Guildmage makes your army a nightmware to block, and it ensures those that double block have a higher chance to eating the dust as well
They can deal with threats and enable powerful creatures