I only, just now, realized this forum existed... and I've heard that people might actually get help on this forum.
Here's my thoughts on this...
1) I'm aware there is a warning... but that is not "plenty of warning" like most other people, I did not see it at all. It's a little addendum tucked into a pile of 4.0 hype. That's not adequate... and even if it were, a warning has no value if players aren't given adequate time to actually do something with the warning. The HK-51 quest is crazy draining, because you can (sometimes) search for over an hour, re-trace turf you've traced over before... and still not find a component.
2) This exact same issue occurred after the last major patch. While we may have been warned the quest could reset... the community manager over on the SWTOR forums said he was going to take steps to ensure this never happened again.
http://www.swtor.com/community/showpost.php?p=6761606&postcount=16
...so, sure, we were warned (hardly), but we were also told this wouldn't happen again.
3) The last time this happened, it upset enough people that steps were taken to actually fix the issue. "Sorry, won't happen again!" wasn't good enough, the heat was on, and once again, Community Manager Eric Musco came forward to say "ok... we'll fix this."
http://www.swtor.com/community/showthread.php?p=6762900#post6762900
....so, as far as I'm concerned, I've got an Official Post saying that this is something that Customer Service Can & Will Support and then, a whole bunch of posters came into the thread to say, yes, their quest was fixed, and even, in a lot of cases, accelerated to the final stage (where the CSR couldn't determine which pieces were found).
Honestly... certain parts of the quest are fun. Finding the pieces? No... not that is not even a tiny bit fun. I have no intention to start from scratch in tracking down those pieces... not when plenty of other players with the exact same issue have actually received CSR solutions for the exact same issue.