As it is its actually balanced, but rather bad if you cant curve into FA. So that means Druid needs more Treant support for this buff to reliably work, but there are still 3 Druid class cards coming so not all hope is lost.
I doubt they're getting more treant support than what's already been shown, but maybe. Summoning 3/3 tokens from a lot of the treant summoning effects is already pretty powerful. This doesn't just curve into Forest's Aid, but also Whispering Woods into Soul of the Forest.