It took me a good day to read through all of these posts, but now that I have I'd like to put in my 10 cents.
I've only been doing reviews for EF since December and I've loved my time here so far. I don't plan on going anywhere once the free reviews are gone either, but I think a lot of good questions have been brought up so far.
I'm sure once free product reviews are gone there will be a good handful of reviewers that leave and while I understand wanting to reward seniority at EF, I think review quality is just as, if not more, important. I know there are a lot of reviews post on a daily basis here, and monitoring them all would be a challenge but I have a few suggestions on how that could be handled:
What if all reviews, in addition to having the current rating system, had an option to be flagged for additional review by a mentor? That way if you stumbled across a review that was lacking it would be brought to someones attention and suggestions could be made to the reviewer on how to approve. If the same reviewer had too many flagged reviews they could be required to partake in the mentor program again so the quality of their reviews improves. The flagged reviews could be looked over by any mentor and that mentor could be given bonus points for taking time out of their normal mentoring to help someone. If the same reviewer is flagged multiple times again and required to go back into mentoring a second time a decrease in buyout discount could take place. Inversely if a reviewer is consistently posting helpful reviews an increase in buyout could be give as a bonus. This way someone isn't penalized harshly for one bad review, new comers are not starting at a disadvantage, and you are rewarded for hard work.
The most obvious question so far is regarding shipping on buyouts. I think free standard shipping should be given with buyouts and then also provide an option for expedited shipping at a cost. Especially for the international reviews shipping costs would make reviewing more difficult to afford on a regular basis.
I think one push and one DR is a great idea for new products, that way there aren't new items sitting for months without a review on them. I think it would also be wise to extend this to cover products that have not had a review post on them in 6 or more months. That will keep the product reviews fresh and allow for more people to get a surprise present on their doorstep.
I'm sure there were other points I meant to cover, but I think until specifics on the buyout discount and points awarded are decided upon that this could be used as an opportunity to revamp the review system and award those that deserve it.