Don't nerf existing food items
This is a very understandable sentiment, especially for those that have worked hard to get a stash of food ready to go.
However, I also think that some of the current food items are .. unbalanced. And another important factor is that stamina bars only go up to 100, so there's only so much room to make more complex recipe/high value food items.
If we assume nerfing is necessary, I can see 2 options (and yes, I am making some very wild ideas here)
1. Existing food items are nerfed, but all people are gifted new food items equal to the amount of stamina they lost out on due to the nerf. Is this possible? I don't know, but it would make the nerf hurt less. However, it would still leave the issue of keeping your stamina hoards filled on the long run. So other things that would very much need some serious additional balancing in order for this to work, such as better and easier rewards through things like hunting, farming and campaigning. (For example, moths are reduced from 15 to 5 stamina, means that encounters that usually dropped 1 moth should now drop 3, so that at the end of the day, the rewards in terms of stamina value remains equal). Another important sidenote is that this addiitional balancing needs to happen at the same time as the nerf, as to impact users as little as possible.
2. If existing food items are nerfed, and it is not possible to give out foods to keep the values of our stamina hoards the same and increase the rewards of current gameplay, another option is to also nerf the stamina usage. So if 'basic' grey-rarity raw food items are reduced from 5 to 2, that means that activities that generally use up 5 stamina should be reduced to 2. Professions which usually take up 25 should be reduced to 10, hunts (which use the entire stamina bar for some reason) should be reduced to 40, gauntlet to 20 etc. Make the amount of stamina you need to do things experience th same reduction as we'll see in the value of items so that at the end of the day, it doesn't hurt the casual player.
Introduce a foodpile instead of feeding food items per wolf
And if we don't nerf, how would that work? How can we still make the complex recipes worthwhile with this hard 100 stamina limit? Easy; instead of feeding food per wolf, food is converted to a food pile. Autofeeding draws from this pile. That way 1. you can have food items that exceed to 100 limit, 2. you don't waste as much stamina points whenever your wolves don't have a multiple of 5 in their stamina bar (e.g. having 4 stamina left, still uses 100 stamina to fill it up all the way now, but if you draw from a pile, you can use exactly 96 stamina to fill it up)
Complex recipes are hardly worth the effort
This is something that has been said since beta and EA. Cooking takes a long time, requires multiple ingredients in a very limited-size pot and sometimes requires the same amount of stamina input as the output (and in some rare but horrible cases more!)
9 out of 10 times just cooking simple recipes has the best stamina output in terms of effort and time. I understand wanting to make compelx recipes more worthwhile, but that doesn't require nerfing existing simple and raw foods.
Make pot size limit apply to amount of recipes in queue rather than individual ingredients required
Instead make the pot size limit apply to the recipes rather than the individual required ingredients. So instead of only being able to make, what is it, 4 or 5 pumpkin pies, because that's the amount of ingredients the pot can hold, allow us to make the recipe 20 times if our potsize is 20. The extra time and extra ingredients and higher level requires to successfully make it, are enough of a wall already to make the complex recipes 'complex'.
Increase stamina value of complex cooked items OR Lower required ingredients
Another thing to make complex recipes more worthwhile is either increasing the stamina value (so that it is a significant improvement to the separate ingredients) and/or lower the ingredient amount.
More than 1 item as output from complex recipes to bypass the hard 100 stamina limit per item
Another idea is that instead of going beyond the 100 stamina on an individual item (because of the stamina bar limit, and assuming we're not going to do the foodpile thing), instead of resulting in 1 item, you can get 2 items as a result. So for example, instead of the current ingredients for pumpkin pie giving 1 pie, it gives 2 pies to increase the value of the output without going beyond 100 stamina on a single item.