I also posted this on the restaurant board this morning. it is long but I think it is a good perspective when dealing with mixed reviews on places, or the notion that everything is going downhill at disney. I will just c&p it here. But I was thinking about it and I really do think this is the reason.
Honestly I think that if you are going to WDW frequently, it kind of loses it's luster a bit. Places like this site tend to attract people who are frequent disney visitors. Any treat, had over and over and over again, begins to feel like less of a treat. Also the more you go, the more chances you have for places to have an off night.
I noticed this when I was going 3-4 times a year year after year and then due to personal circumstances took a break for 5 years - my next trip was probably the most fantastic ever and the dining was great - not at all "downhill" from years past imo... but then it was a real treat and it had been so long since I'd been to any of my old favorites... everything was fun and nostalgic and I just had a great time.
People have been saying that Disney is going downhill for as long as I have been going. "This" is worse than it used to be. "That" was SOO much better in 19xx. If you have never been or haven't been in a while chances are good you will have a great time and the restaurants will be great if your expectations are set properly. The buffets are not vegas quality buffets where they have incredibly rich and expensive foods and they are so huge that turnover is so quick that everything is virtually cooked to order. But I have always found most of the food on the buffets to be hot, fresh, tasty and filling with the occasional end of a tray being out too long and would avoid it until replenished. Most of the buffets I go to are for the character experiences, which have always been at least good, with my kiddo glad to get hugs and signatures without having to wait in line... some much better than others but all head and shoulders above having a whiny hot child standing in a slow moving line for a character.
I mean no it is not 5 star dining in some major metro area with a famous chef (Except for maybe V&A) but as an overall experience, the food is really good. If you are used to inexpensive restaurants and live in a low cost of living area, the prices may be shocking... but realize you are paying for location and and immersive experience as much as food quality. In many places a $40 meal would entail something like lobster or filet or maybe both but that is a bit below the average price of a standard character buffet dinner and you won't find either of those things on the buffet - any meal featuring those things will be significantly higher. People from major metro areas will have less sticker shock.
The theming and entertainment in many restaurants is amazing and immersive, and service is usually really good too. There has, over time, been a bit of homogenization of menus across the property (which you will see if you read all of the menus) but again unless you are a frequent visitor or staying for 3 weeks and eating everywhere, that probably won't effect you. There is plenty of variety to keep someone in at least 2 weeks of daily restaurants without feeling like you are repeating yourself in menu or theme. I have two a day planned for a week and there are still things I am not getting to.
The other caveat is that if you live in a place with amazing local cuisine and Disney does their version of it, I would avoid it. It will invariably be a disappointment. I live in New England and compared to the lobster rolls I get here, the thing at columbia harbor house looks like cat food on a hot dog bun... but some people love it and find it quite tasty. If you're from a place that has stellar bbq you may not find the bbq at WDW to be anything special. I am breaking my own rule and trying Sanaa on my next trip even though I have had excellent indian food and even make it myself so YMMV on that as well. We'll see
Chances are if you live in an area with an amazing Ethiopian restaurant you will find the african themed places at WDW to be kind of meh. you get the idea. People call this "dumbing down" and are highly critical of it but honestly I don't have a problem with Disney making the food appealing to more tastes - as long as it is still tasty, I'm good even if it's not 100% authentic.
Everyone has a truly off night and sometimes you get to a restaurant when it is having one, but after being a DVC member since 1999 and a member of these boards since 2000 I will say that the grumbling has been going on for well over a decade and if the quality has been dropping as much as people have said over the years, they'd be serving dog food by now. Believe me, it was never THAT much higher than it is was on my last trip. Maybe a bit more variety and a bit more innovation but not so much that it is not worth dining there now.
I keep thinking that it mostly is for theming and the atmosphere you're eating in. Food may be great but may also not be the best you've ever had. 
