It does get a little better with Rat tokens, but Id still steer clear of it most of the time Giving up food to hurt your opponent can definitely have a place, and even be a win condition, and the base line of the card as a three mana 3/2 that makes a food isnt a disaster Even without the enchantment part, youd always play it in your black decks
Look closer, however, and it becomes even more apparent why Umbreon ex is so sought after, and why it may well see quite a bit of play, following the release of Prismatic Evolutions
Of course, making another 1/1 Saproling seems small-ball for Xaviers ability, so Id be on the hunt for something that can make much bigger token creatures, such as The Skullspore Nexus, or copy spells like Cackling Counterpart
Its first ability makes this blue dragon almost invulnerable to spot removal unless it's the only legal target on the field