No, my lunch break is by far not long enough to actually sit down and type my opinions about these three items (or banes) of fanfic authorship. However, it was long enough to stumble upon these essays by Rhiannon Shaw, who - most likely - said it much better than I could have. :)
In Defense of Original Characters
How NOT to write feedback
and constructive criticism
In Defense of Original Characters
How NOT to write feedback
and constructive criticism