This is a very interesting idea. I would however not allow for delegation of reputation votes as the whole idea is they are supposed to be based on folks making calls on their own.
I also feel like some amount of clarity on the current system would be beneficial as this is the first time I've seen how it's calculated.
You can see my past posts on reputation at the following link. In my earlier posts, I go over how the current ent system works. I also provide a simple flow chart as well.
https://peakd.com/@moeknows?filter=reputation
As for the proxy voting, we've discussed it on other comments today. It doesn't have to be included, but I'm not sure how it would be used in a malicious manner. As it's effect could only be spread to 50 accounts, I fail to see the incentive to use it other than to consolidate the voting of one's alt accounts. Can you think of another nefarious reason someone might exploit proxy voting?
I don't think it's nefarious as watering down what you're proposal does by making it super easy to artificially inflate things with an alt.
But since it's stake based, does it really matter? If you control both accounts, you would just vote the same in both accounts anyway. Proxying would just make it a little easier and would actually make it impossible to self vote in such a situation.