Hi! I developed the new pet intensity calculator linked above. I was actually going to bring it up when you were redesigning the animal lore gump, but I wasn't sure on my release date and didn't want to delay yours.It requires to consider all possible starting slots (value that may vary for several pets and cannot be obtained after training), also it considers the spent training points (again it cannot be obtained and I can't know how many times you trained a pet and neither if you have trashed some points). It seems that tool has lots of specific formulas for specific pets, and I don't know if it can be generalized...
Also as said above, the pet training is a very personal choice, how can you say that a pet with all res to 80 is better than another with all res to 70 but has more skills or stats? I mean maybe you are just training a pet for a specific purpose (like a pet designed for a specific boss) and you don't care about certain stats...
So I'm unsure about the whole thing...
The formula is pretty generalized and can be applied to any pet. It does require some additional information to the CreaturesDB file though (base damage, slot start, slot max, innate magical abilities).
I actually branched off a version of your Animal Lore gump (before the rework) and added my rating system to it to help me gather wild pet information for testing:

It's not 100% up to date with the version I released on the website, as it doesn't include the % rating (but that is easy to add), and it doesn't detect control slots. The control slot detection should be possible to add, as its actually a formula based off of the pet intensity and its pretty accurate.
Some things that wouldn't be able to be done in the UI would be the resist thresholds (which I don't think is necessary for the UI), and there would probably be some issues with legacy pet ratings (might be able to detect if a pet is legacy based on the intensity, similar to control slots). Leftover/trashed points wouldn't be doable, but that's a small part and only relevant to the trained pet rating.
If enough people would find it useful and you wanted to add it to your new animal lore gump, I'm more than happy to work with you on all the formulas used to generate the ratings.