Well, I am enjoying it for the most part. Main character for Co-Oping is a Warlock, but am Soloing as a Titan.
Co-oping is pretty much a must for maximum entertainment in campaign mode, as the story is pretty non existent overall. Unless it has already been announced, can anyone else foresee official canon Destiny novels? It is a bit disappointing to have such a decent concept, but fail in one of the parts of a game that they usually liked to keep as important.
I think Bungie may be going a bit too far, now that they saw how well the Halo novels were received. This time they don't have a main character to really play off of initially, so it could work either way with a decent writer. ie no crutch, but lesser ties to the game.
And the "Grimoire Archive" is kind of crappy considering if if you play through the campaign, unless you find all the entries, you will never get a full picture of every detail in the game. It's like they wanted to make a guide/art/info book, but want you to work for it. This is the same garbage that Final Fantasy 13 tried. Too much text, not enough explanation in the actual game. ie poor storytelling.
I don't know if it gets any better, as I am only just finishing up the Moon at the moment... But I am totally not engaged in the plot.
Shooting things with friends though, that I can get behind.
But co-oping can make any game better (ie Aliens: Colonial Marines)
I honestly would have to give Destiny a 7/10. It's really nothing "new" and the campaign is sorely lacking in actual story. Still fun to play, even more so with friends.
As a footnote, this is based on the campaign and PVE content only. I am not a PVP kind of guy, and usually do not bother with PVP portions of a game.