Item #1 is pointless to complain about now. There is a ton of content at this point. Even as a day one player I understand that yes we have done it all but that doesn't mean that there isn't 2 raids, POE, Trials, Iron banner, original story missions along with 2 dlc's story missions, plenty of strikes, and 4 regular pvp modes and 2 additional rotating each week.
Item #3 is repetitive in itself
Item #4 You dont have to do reputations with anyone that you dont want stuff from. It's only a grind if you make it that way. Most of the factions dont have anything worth getting anyway unless you find a particular item intriguing.
Maybe it because I played a lot of WOW back in the day but this game is not a grind. Especially after they fixed the material farming issues. There is nothing that you have to grind out anymore in this game beyond rank 5 IB but you can get there 4 or 5 hours over a few days and even quicker for your 2nd and 3rd characters. A real grind is doing the same raids each week with a group of 20 hoping that your classes item for a particular slot is one of the 3 item drops from a boss and also hoping that you have the DKP to get that item. Thats a grind.
There are problems with this game but the only ones I see are a poorly written story. No private matches to promote competitive destiny play and a complete lack of purpose for clans. New exotic weapons cant compete with ones already in play. Almost forgot the demise of the auto rifles as well.