More interactions with the crane fly and gnat would be a nice boost.
"Play any number of bats for free, then draw all bats from the clearing onto your hand."
Or straight up allowing you to use both clearing and hand bats, since the bats will be 'flying to you to get that gnat'.
Or give gnats and crane flies different multipliers depending on the number of gnats or crane flies in your forest.
1 Gnat: 1x1 per bat.
2 Gnat: 2x2 per bat.
3 Gnat: 3x3 per bat.
This follows the rabbit example, but is limited to three as there is no more gnat cards than that.
If you have the woodland expansion, you can get three crane flies, who can also give you 1/4/9 multiplier.
The gnat/crane fly multiplicator would force the same 'need to deny this card' dilemma of the wolf, but that is perfectly fine.
It is very strong at 3, and gives bats a chance at 2.
Having all expensions gives us total numbers of:
6x3 bats (18) x 5
3 gnats = 18 x 9 = 162
3 crane fly = 18 x 9 = 162
bat cave = 18 x 3 = 54
If you draw and use all 18 bat, 3 gnat, 3 crane fly cards and the cave, you get 378 points. (not accounting for cards that have both)
Realistically, you are looking at far, far less, as you would be denied the insects if possible, each of which more than halves the multipliers, and you have neither the trees needed to play all of this, nor the chance to use the cards below the third winter card.
The limiting factor of bats would be trees, the limiting factor on deer and wolves are cards to discard.