Quoted By:
The main issue I had was that some of the Deltas didn't bear any resemblance to their original forms, making it hard to identify them.
See pic related. Delta Golem looks absolutely nothing like vanilla Golem. On the left, there is Alolan Golem, which is very clearly a variant of Golem with its own distinctions. I'll admit Delta Golem is an extreme example, but it illustrates my points well.
The most important part in retaining the features of a mon is the face. The face is a major identifying feature, and changing facial expressions alone can bring a new look in the Pokemon. Recall Alolan Persian, one of the more negatively received variants. The major change was in the face and it made Persian look completely different despite the body being nearly the same.
Now look at the Golems. Delta Golem has a face consisting of a single eye, completely different from the two eyes and open mouth of Golem. Meanwhile A-Golem adds a beard, brows, and stache but retains the mouth and eyes, being near identical to Golem.
Almost every Pokemon has a face. Look for the face shape, eyes, nose, and mouth and try to keep them or edit them slightly.
Now the body. You can definitely take more liberties here in making your mon unique, and you should by all means. A-Golem is meant to be a variant, and it accomplishes that by having its own features (small arms, big ass taser, feet, hair) while being similar in body shape and style.
As for Delta Golem, I'm not sure how far the modifications are meant to go in context of the game. What I do know is that the only thing it has in common with Golem is the round body, a trait shared by hundreds of other monster designs. The dual coloration, moss, and extra limbs are way off from Golem. I think Delta Pokemon was all about making them perfect for something, but when perfect is a complete overhaul, you should seriously reconsider the design.