Your fleet shard seems to be slightly weaker than mine. I don't consider mine to be extreme. Yours may have been extreme before the split, but what you list is not extreme.
1) and 4) are irrelevant for the subject.
2) and 3) are slightly weaker than my shard. My shard has 0 (zero) rebel fleets in top-50. They are all Negotiator/Malevolence. 43 of them are at 7*. When climbing I see that none-R7 fleet commanders are VERY rare (almost nonexistant).
5) You only have yourself to blame.
I also have an alt on a much younger fleet shard (late 2017) which is considerably weaker, but you can't really compare the two.
