Agreed on both counts. The main game of Borderlands 2 is absolutely amazing, even moreso for me due to the co-op experience. The DLC was rather lacklustre I thought, but I was kind of expecting it as Gearbox outsourced it.
As for the online grinding issue, it really annoys me too. It's a very cheap way to keep people playing the game and unfortunately for us OCD trophy hunters, it works.

I don't mind the odd progression trophy here and there, but one for prestiging 3 times? That is madness.
Big congrats on your completion percentage. I thought mine was good at 94% but wow, yours is something else! I saw that you mentioned a "DLC Overload" in your comment. Was that part of a big clean up to raise the percentage? If so, kudos!