Sarno said a lot of the things I was going to say, but since I already typed it, here it is:
I love posi-negs. I would even say that I’d like to see more of them present. I do think it should be more of a chosen playstyle rather than the defacto though. I especially love trying to build a build where I turn negatives into positives. (for example a node that gives less health in exchange for more damage might be really nice for someone that is building ward/dodge defenses.)
One thing that makes the negatives feel really bad at the present moment is that you can inadvertently gimp your build by taking the wrong and the mechanics to respec aren’t in yet. I imagine that it will feel less bad once respec mechanics are in place (which are currently being worked on).
Devs are working pretty hard on putting descriptions for effects into skill tips, I imagine this will continue to improve with time.
Should be in the next patch 
a bug. Should be fixed soon as well.
Devs confirmed eventually, but no timetable as of yet.
This is likely due to only a small number of unique items being currently implemented. More uniques will be added and drop rates may be decreased for uniques when loot tables/chests are implemented meaning it will be much less likely for you to get duplicate uniques. As a side note the implicit values are still randomly rolled for uniques, meaning some are better than others even if they have the same name.
One of the nice things about LE is that even white items can be desirable. Adding more affix tiers would likely dilute this. The devs are planning on legendary equipment, which is as far as I understand it, supposed to be like uber uniques. In addition they’re planning on adding set equipment as well.
The memory system:
would probably be a fairly similar system (that also wouldn’t break the limitations of the skill tree)
Personally I hate this, although a lot of people have requested it. Devs have mentioned that they may look into adding it as an option (although non-obfuscated controls take precedence for them)
on my acolyte I play no health high ward… having ward be used as a health cost would be highly undesirable and detrimental to that playstyle. If it were a node on some skills that cost life, it could make sense but would likely take a lot of mechanical tweaking for a node that’s likely to be used rarely.
nom. nom. nom.