Your personal enjoyment is great, and at the end of the day that's all a game has to deliver to you. But while it does a lot of things well, it fails to do anything on a greater scale than what can be provided elsewhere in the eyes of reviewers. That's where the 5s and 7s come in.
It's the jack of all trades but the master of none.
I saw the Jack of all trades/master of none comment in the polygon review and it's quite silly from them to be honest. You can only say that if there is another game that attempts to blend the genre of gamming(trades) like Destiny did and then did better in some extent than Destiny to provide a better experience(master).
As I see it, there exists no such game like Destiny. There is no game that provides a similar holistic experience. What Destiny tried to do, they were first to (I had a friend who told me MAG tried a bit but it was just masses playing online), so you can say they didn't master their subject. Destiny isn't trying to be like borderlands or world of warcraft... it is trying to be something different and provides a differnet experience than both.
A reviewer like Polygon (and the 5-6 others who gave it 60% or less - Okay, only level.nu gave it less but you get my point) are just doing the same thing... comparing the game with what they want it to be... The game delivers on its promise (it's a fun and addictive game that's logging in record number of hours on current gen). It isn't just me... when playing online... I've rarely found people as involved and engaged in playing... it's nice and enjoyable. :)
I am a Gamer... I play games and not consoles. I have a PC and Console on which I game... I like games. End of Story!