Do you have an alternative source? If not, we can assume this is cannon, because, despite it being cut content, it is still cannon.
The whole point is that the HK-51s were lost for like hundreds of years and then found on Ilum....
You asked for my unbiased evaluation of the HK's battle effectiveness. I gave one. What's yours?
what are you talking about? HK-51s under the Empire's control were lost for a decade and then turned up on Belsavis. How were these 51s constructed? how much tweaking would have been possible within those 300 years? do you really, honestly believe that if someone found the HK-51 schematics they wouldn't try to make some improvements before producing a shipment of them -for the Sith Empire-?
kotor 2 is my unbiased evaluation of the HK's battle effectiveness. They got roflstomped at every turn.
You say what Sith Assassins do is a myth, yet what have HK50s done besides pose as a protocol droid to stalk 1 jedi? nothing, lol. They're not nearly as powerful as you think, especially if the HK-51s are anything to go off of.
You say HK-47 was reconstructed from HK-50 parts. That's true, HK-50 parts were compatible and in some cases the same as HK-47. Were they as strong as HK-47? Undoubtedly no.
And yeah, an HK-50 could probably take a couple of goons. that's about it.