The HW argument has merit, for sure. However, aside from the nature of the division that makes win streaks difficult to attain, I think the kiddie-pool depths of the division, and the lack of truly great HW's is also a reason we haven't seen many 5-10 fight win streaks.
Junior's run was impressive as fuck as well. He ran into a prime Velasquez, who is a greater fighter than Fedor ever fought. Stipe's current run is impressive as fuck (doesn't get near enough credit imo). The quality of guys he's putting away counts for a lot of cans on Fedor's record (lots of Japanese, that giant Asian, Fabio....who Stipe creamed).
Agreed that Fedor fought relatively bigger guys than Georges (relative to themselves), but I think we both know what would happen if I took the time to compile and compare their opponent's win-loss records. Beating better guys is more impressive than beating get bigger guys imo
As for Fedor's loss being "bullshit", you can absolutely make that argument. But in that same breath you can definitely make a case that his win over Arona (a smaller man, since size of opponents is a key component of your argument) was bullshit.
Arona dominated that fight from top position, and I think all would agree that judges in any current promotion would be expected to award Ricardo the clear winner. If I remember correctly though the judges operated under a strange rule-set that awarded Fedor's ineffectual striking from bottom, but more importantly denied Arona the ability to to strike from top/mount or something like that (which could have spelled the end for him a la the Bigfoot fight).