Currently, wow heroes has the following weights for glove enchants:
18 - Mastery (50 Mastery)
20 - Greater Mastery (65 Mastery)
20 - Heavy Savage Armor Kit (44 Stamina)
44 Stamina is significantly less beneficial relative to 50 Mastery. This is especially true for plate wearing tanks (I'm not sure about druids).
The Armor kit should probably be 17 or 16 rated.