Squirrel isn't just bad, it's worse than rolling.

Squirrel costs 3 and sells for 1, allowing you to roll three extra food items for the price of two rolls that would normally get you only four food items. The value of the Squirrel over rolling twice could be said to be one and one half food rolls. If you do not sell the Squirrel on the same turn the value can only be said to be an additional half roll, as you would otherwise be rolling three times for six possible items, one less than that the Squirrel gives you.

The take away here could be that the Squirrel is marginally better than rolling in terms of value, but there is also a large opportunity cost to playing the Squirrel. In three rolls the player would encounter fifteen different friends to buy or freeze, that could represent a few opportunities to level up a friend, buy a powerful unit for your build, or find a temporary power increase such as a turtle or scorpion. When you roll with Squirrel, you gain three food discovery options and lose out on fifteen friend options, considering that the number of minions you see could directly translate to winning more games, do you really want to see fifteen less potential friends than your opponents? You have to be pretty confident you won't benefit from purchasing any more friends if you want to play the Squirrel. This is a catch 22 of course, if you buy the Squirrel, you will benefit from buying any other friend, right after stunting your ability to do so.

Finally, the Squirrel takes up a space on the board. Getting rid of a friend that may benefit even slightly for this thing is just a bad idea. The limited value you get from this friend is not worth the increased potential to lose. Assuming you do find something you want from this shop, you will only get two rolls after the 6 gold investment to buy a replacement minion.

TL;DR: The Squirrel robs you of potential friend upgrades while providing only a marginal increase over rolling for food. At the same time it robs you of potential replacements that you will need to fill this 2/2 void in your party.

Here are some suggestions:

Tier 4 - 2/2: Buy, replace the shop with food items that cost 1 less.

Tier 4 - 2/2 : Buy, Permanently increase the number of food shop slots by 1. (up to three times)

Tier 5 - 5/6 : Replace (1/2/3) friend shop slots with food shop slots while this friend is in your party.