I added myself to the PTS and spent a couple of hours running around before this last patch release and can't help but feel that what I did and was able to do in the limited time I spent was of little value.
I rolled a noob but frankly did not have the time to progress it far and so really had no way to test the sort of things that could have avoided bugs.
I rolled a VR14 and took a peek at Upper Craglorn but I had all trials gear and nothing familiar and thus again barring being able to see that Dragonstar loaded fine and can kill a solo NB in unfamiliar gear I couldn't tell you much of value
I suspect most people in PTS will have limited time and so will not be able to test more than a little bit before actually playing the main game so... perhaps there are ways that ZOS can get the best out of our limited time.
Obvious option: Port over existing characters on request - the advantage here would be that within 5 seconds of loading I could have told you Night's Silence was broken (for example) because I would have been wearing it. Plus with all familiar kit and skills ready players would know instinctively if content felt right or wrong in terms of response and difficulty and would be able to test better.
Assuming this is not possible - consider the option of adding crafting materials to the big bag of goodies you supply the VR14 build and making PTS toons automatic 8/9 trait masters. That way we can at least outfit ourselves quickly in our preferred gear - again making it easy for testers to test content against the actual gear they are going to be using in live play.
Consider allowing us to roll various level characters not just 1 or VR14. Why not offer maybe a level 35 or a VR2 option so that a variety of content can be checked at various levels.
I have no idea how feasible this stuff is but right now, judging from the immediate reactions to 1.4, I don't think the testing we are doing is uncovering the problems you need to know about.
I'm sure I will be moaning about that elsewhere so this is my attempt to offer something constructive to allow us to help you avoid bugs in future.
GM - Malazan
Raid Leader - Hungry Wolves
Legio Mortuum