I have learned from life, reading reviews and knowing a number of professional reviewers is that EVERYONE has a frame of reference and personal preferences and these will influence a review.
When I do a review (I am far from a professional) my personal preferences of food, ship decor, service, cabin size and amenities are a focus and what I consider good, fair and bad will be different from what others may have. I personally disliked, really disliked, the Epic's cabins but others may not have a problem with them.
When doing a ship or cruise review there is no way anyone can be truly objective unless all they are going to tell you are: GRT, number of dining rooms, length, draft, beam, etc.
In reading reader reviews I throw out the "Everything was perfect" or "It all sucked" reviews and look for something that relates the good and not so good. There can be good information in the "Everything was perfect" class but you really have to do some interpretive reading to figure it out. The "Everything Sucked" reviews the person probably had one or two things go wrong and that jaded their entire cruise and you have to figure out what is legitimate and what is overblown.
I don't want to offend but the statement, about food, that drives me nuts are: "The food was great. As long as I don't have to cook it or clean up then any food is great" This gives no information and if this is truly the attitude of the writer then it is a reason why the included cruise line food has gradually lowered itself to mediocre.
Reviews are great tools but like any tool they have their limitations and can't be the only thing you base your cruise decision on no matter if they are professional or reader reviews.