There is no need to brake the rating down into bits on this site. Something you also do with the review itself. It doesn't read as if it's one coherent text but instead you address bullet points like you would do with a shopping list. This review leaves me with more questions than answers. For starters:
From Combat evolved to the famous half life and halo 3 with its revolutionary multiplayer does ODST the latest game in the Halo franchise live up to its legacy?
What does Half Life have to do with the Halo franchise?
First thing that bothers me with this game: how come something that would have been considered an expansion set some years ago is suddenly a full price retail game? You're not dealing with this issue. You only mention it has only 3 new multiplayer maps but nothing about the quality of these maps. Are they any good anyway?
You also don't mention if and how the dynamic of the game changes, since you're "just a human" and not master chief.
I also wonder what is the game for you at it's core? It has missions it has day and nighttime and you play a rookie. What I'm missing from your review what's special about ODST that sets itself apart from other shooters where you're a space marine in the future. Or isn't there anything? What about ODST makes it more or less awesome then Killzone 2 for example? Why should I choose ODST over Gears of War?
And how come that the only woman in this game with enough screen time is your commander but no one takes her serious? Some people reading on this site are very interested in topics like sexism in games.
Finally my personal opinion: a 7 is a too high rating for a glorified expansion pack, especially for full price.