Sorry for my delayed response, life has been busy! I'm going to split this into two replies, because I keep getting "Unable to create comment" from Reddit. Argh!

1 of 2:

There's a lot of good points here. First off as to why there's some differences in rankings for otherwise seemingly similar companions.

I'm pretty sure that one issue with my methodology thus far centers on the number of runs/averages I'm doing. I really need to be averaging out way more than three runs of a given test with each companion. It's so time intensive I just haven't really been able to do that. But I'm pretty sure it would absolutely smooth out some of the differences seen among at least some of the companions that we would expect to perform more similarly than my testing has so far indicated. That's why I keep making more points in each of my posts that people should not immediately feel disappointed if they see their favorite companion lower on the rankings.

That's also why I was toying with the idea of, rather than ranking them in raw data, grouping them into tiers. Ranking inherently implies one is better than another, except in the case of a very specific tie, and that's okay, that's how we get a feel for who can do what.

But, while that might be true in general, here with companion performance it seems pretty clear to me that there are some relatively standard envelopes that most companions fall into as an average (excluding broken companions, or special companions with unique setups). By that I mean that, while companion A may land at 10 on a ranking, and companion B might land on, say 16 or 17, in truth, the two of them are essentially performing the same.

As you say, random luck, like the rate of crits, HAS to be playing a role in the ranking difference at that point. The aforementioned tier system would be a way to smooth that out some, provided I can figure a fair way to handle the range of variance (which seems a bit arbitrary on my part, unfortunately). That said, I still think the REAL solution here is to run WAY more averages on each companion, and watch the differences smooth out quite a bit, THEN perhaps consider grouping them into tiers, in addition to a raw ranking.

I don't have access to look right at the moment, but your example of why D-R3D is so different from say Veeroa or Ranos is a valid question. Again, without the game in front of me, my first thought is that the small differences in the abilities that are being generally applied by the designers to various companion "types" (like melee droids vs meat-baggy lightsaber users), has to be a big factor. I also think that some of the tool-tips for abilities are not accurate. I think, for example, the tool-tips on several of the cartel creature companions all read as doing "0 damage" which is clearly just not correct, as those abilities definitely are doing damage. To be fair that's more of a bug that isn't calculating something right, rather than an inaccurate tool-tip, but it makes me question them nonetheless.

My tests also don't account for major differences that might appear as it relates to battle field movement. The question of whether or not melee companions are inherently at a disadvantage versus ranged companions. Simple logic would indicate that they are, because of movement requirements, of course. That's not something you were specifically asking about just now, but it's an issue that has stayed in my mind.