Not personally, but it does effect my lasting appeal of a game.

Say for example Halo 3. Best MP I have ever played, but then after a couple of years the match making and map repetition became troublesome and they got rid of Rocket race, it ultimately left me very dissapointed by the game, but I will always remember it for the first few years when it was great.

Well, in that case..... If the game is a re-release, it will probably lose points for being older and having the bar raised since its release, not improving on past mistakes, or just having a different reviewer who doesn't love it as much.  Sometimes, it the game is similar enough to other versions, it just gets the same score/review.  The bonus content may get a mention but, if it doesn't add anything to the experience, it won't add anything to the score.

How do you define optional though?  What's essential in something like Smash Brothers and what should get a separate review?  Can't change the rules for something just because it's a rerelease so you have to come up with a criteria that works for all games and defines what is essential and what is optional.

 I personally think that you have to review the entire game regardless, because what's optional to one person could easily be the only reason someone else is buying the game.  You just can't predict things like that.

The OP stated that it was released later on right? That's something that is optional. You don't need it. And some people may not even want it.

That optional thing should get a seperate review since it wasn't in the original game. Something that isn't in the original game should be counted as optional. (Unless it's a patch or an update that doesn't affect the story/overall gameplay of the game.)

That's what I think.

There are Multiplayer games like CoD, Counter Strike, Battlefiled, Tekken etc. where MP is essential and those game should have good Multplayer, and they should lose points for crappy MP.

But games like Bioshock, God of War or Assassins creed should because who gives a shit about those Multiplayers?

I'd say no. Plenty of my favorite games have had features that i've ignored, like Farming in Monster Hunter Tri. So long as the bad experience is really auxiliary, and not actually important to the main game.

You don't care, but those games are adding multiplayer to try and broaden their appeal, and you do that broadened audience a disservice if you ignore the thing that is drawing them to the latest iteration of any particular game.  

Woh, woh, woh! I wasn't saying that something like MP shouldn't be counted in the score. I was saying that something (DLC) that is added later to the game should be.

We need a specific example of this happening. That specific example is Resident Evil 5. Did the additional content improve or damage the experience? It's totally optional, right? It was added after the fact and it was re-released with the additional stuff as Resident Evil Gold.

Ready. Set. Go!

If it's released as DLC for a game you already have? No.
If it's included with the original game? Yes. (For example, I would count Multiplayer for God of War: Ascension as a included feature because it's included with the base game, sure it's optional to play, but it's part of the original package).