Dear Cristi,
You have written a very attractive introduction to your research while highlighting its solid connections to the contest topic.
A few specific comments:
1. I really enjoyed the playful example at the beginning. While the importance of isomorphisms between seemingly different structures is well recognized by physicists, mathematicians, and philosophers of physics, I believe there is still plenty of room for it to be recognized by people in general, and your example nicely serves that end.
2. Although I had heard of Klein's Erlangen programme, I did not really know what it was about. Knowing that it was based on the recognition of the importance of invariants has caused me to revise one of my beliefs, namely that the general recognition of their importance occurred largely as a result of their importance in relativity (Evidently, Klein anticipated Einstein in this regard by over 30 years). So your essay did change at least one belief, ha!
3. It is interesting to consider whether the notion of fundamentality is purely epistemological or can also be framed ontologically. While I perceive it as a former, I am open to arguments that it can be the latter as well. However, here is a challenge for any ontological fundamentalist: At bottom we might consider the fundamental difference in physics to be between being and non-being. Which is more fundamental? It seems to me, either answer one chooses is open to a counterargument: If one chooses being, then it could be argued that being can be reframed in terms of the absence of non-being, and if one chooses non-being, then it could be argued that it can be reframed in terms of the absence of being. My point is that either choice seems to me to represent a particular worldview, or paradigm, and that makes it inextricably epistemological.
4. The phrase at the end of page 6 "Also they [the GUTs] didn't explain why these particular representations out of infinitely many possible for each group", resonates with me especially. So much of contemporary high-energy theory seems to me like a sophisticated game of pattern-fitting without trying to understand what the patterns really represent. I am often reminded of Feynman's example of the ancient Mayans, who had a sophisticated framework for predicting eclipses and the positions of Venus, but not even a basic concept of planets and the solar system. To me, that is not a secondary but a primary problem with many contemporary approaches to understand nature more deeply. I laud your efforts to try to look behind formalisms and patterns to understand the "why".
5. I admit that I did not follow the math in the latter part of your paper but I would like to raise at least one potential concern: It seems to me not sufficiently broadly appreciated that at different scales, the ratios of different powers of the scale changes, and when considered together with any kind of density, this results in different physical behavior at different scales. In short, to paraphrase Philip Anderson, in my view, bigger is different. Would your Indra's net model be able to account for that?
All in all, a very attractive essay.