It would be like sending me to review a Sushi restaurant. I hate sushi, so it could be the greatest suschi place ever, and I would still review it generally negatively because I don't like the basic version of the food anyway.

This just doesn't seem like your most useful strategy here. This is the second Coke Zero review that I have seen whinge about an a funny diet aftertaste. A) I think you are imagining it. I have given Zeroes to ppl who also don't regularly drink diet soda and they don't detect immediately at all. B) If you are a regular diet soda drinker, you forget about that "aftertaste" it becomes just part of the background notes of the flavor. I almost only ever drink diet soda and Zero has virtually NO after taste to my reconning, especially with Diet Coke's flavor which even after years still has a strong after teste to me. Further, the flip side, is, when I do drink an non-diet version of any soda, its so sweet is makes me want to gag–though this is more true with the HFCS sodas than the cane sugar ones.
It just seems to me that you get a diet soda drinker to review diet sodas if you want any credibility.