I'll agree with you regarding the value of features/functionality, even design. I find in comical when members here outright dismiss certain element of a phone as not worth the extra cost when they very well may be very valuable. For instance, a user who is interested in VR will value the best in industry Samsung display coupled with the Gear VR--the OP3 would be a far inferior experience. The camera, wireless charging, waterproof (this is quickly moving up my wish list on my next phone), bigger battery with better performance--hell, even Samsung Pay, all offer additional value, in varying amounts to different customers. The Samsung is packed to the gills with features and functionality...probably more than any other phone on the market. I personally don't want compromise in my smartphone so I have no reservations paying top end prices if I value the additional functionality provided.
But the claim of bias against Anandtech is becoming a bit of a tired troupe whenever they're brought up. In this specific case, their assessment is really about software performance and it's nothing new or unique to them. Make the rounds of any of the most popular Android focused media and you'll generally hear pretty much the same. I listen to podcasts from quite a few Android centric sites (Android Central, All About Android, Material are regulars listens amongst others) and next to none of the staff/writers or usually guests choose a Samsung phone as their personal daily driver. And when it comes to recommendations for devices, Samsung's are rarely first choices and if they are, there is almost always the 'TouchWiz of software caveat'. And there is usually high praise for the hardware as best in industry---but none choose it and it's always software (or update) related. The criticism being levied by Anandtech or pretty much the same as you see across the tech media.