The word 'Cartoony' can be a very subjective word.  It can be very open-ended.  Her definition of Cartoony and your definition of Cartoony may very well differ.  Essentially making your 'opinion' that her 'opinion' has no ground to stand on....and invalid one.    So while you can certainly question it, debate it, argue it.   You cannot act as if it is unreasonable, illogical, or even has bad reasons for having it.

She thinks Mario is cartoony due to the fact that it has colorful graphics and non-sense characters. There's nothing to argue here, that's what she thinks. Why else would she think the game is cartoony, huh?

If the game is 98% 3D (Your words not mine) than what about that 2%?  Is she not allowed to really dislike that 2% that isn't 3D?    Again, you are saying her opinion is crazy, absurd, has no basis to be made because it stands in directly opposite to yours.

Are you fucking kidding me? She wants the game to be more 3D when a good 25 hours of the game already are. She plays in 2D more for 30 minutes tops. That is not a valid complaint. She didn't say she didn't like the 2D, just "Moar 3D". You think there isn't ENOUGH 3D platforming in the game?

In otherwords, You can't say her opinion on this matter is incorrect or false because you cannot prove it. And they aren't horrible reasons. Mario is a cartoony game.  Some people will love that (And have), some people will hate that (and have).  Super Mario Galaxy 2 has 2D parts (True or false?)  That might be too much 2D for someone.  (Again which would validate her dislike for it.).

I can most certainly prove it. The Mario and Luigi games are cartoony as well along with Ratchet and Clank and she still likes them. She is using invalid reasons to construe the idea that SMG2 is bad. 

I think Nintendo fans upset by this need to get over it.  She doesn't like the game.  That doesn't mean she has some weird bias against Nintendo or anything absurd like that.  It means she is disappointed for a myriad of reasons with the Mario series.   I actually agree with that notion as well.

She's saying that she wants more 3D when there's 25 hours of 3D platforming and is being a hypocrite for the cartoony graphics reasons. She's pretty obviously biased.

How has Mario not changed as much as Gran Turismo?

In terms of pure appearance...It's not even close.  Gran Turismo has changed 10 fold while Mario 64 / Mario Galaxy is very comparable. 

You're insane! Mario Galaxy is miles better than 64! Why don't you PLAY the games before saying stupid shit like that?

In terms of gameplay, Gran Turismo hasn't changed much in terms of 'controls' I would say but much of that is primarily due to the nature of game it is.  A racing sim isn't going to suddenly add 15 different controls.   But the physics and all of the other components contained within a Gran Turismo as well as the little fine details all add up and maybe aren't inherently noticeable by the average player but all work towards a more realistic result.

I mean honestly, what has been added to Mario 64.  That is game breaking?  I know gravity,but many games use some form of gravity nowadays.

Let's see....

New Powerups

New Levels

New Playable Characters such as Luigi and Yoshi

More Linearity 

Star Bits that you can use to buy new levels

Entirely new gameplay mechanics that revolve around the idea of moving around on the planet's 3D surface instead of its 2D surface in 64

Not to mention every fucking level is new and creative.

Discount those reasons for Galaxy just being a recycled 64.

1.)  Wait so a game that is has colorful graphics and non-sensical characters isn't like by someone because they said they felt it had too much colorful graphics and non-sensical characters?  Isn't that again the very foundation of a basic opinion.  She feels it is over-done.  Over the top.  Too Cartoony.   Who are you to say which degree is too cartoony.

2.)  Again,  some people are picky SOBs.  That 30 minutesof 2D might have really been a deal breaker for her.  It's just like anything else.  Kill Zone 2 got panned critically for it's controls because they didn't resemble Call of Duty's.  (Well no shit it's a different game), but that doesn't matter.  Everyone has an opinion on a subject.   An incorrect opinion on this would be her saying that a game that contains NO 2D, has too much 2D.  Since this game has 2D portions, she is incorrect in her opinion.

3.)  Again, they are different games.  Maybe she felt they were fitting with what was being presented in the game.  Maybe she has different expectations from DS games or Wii games.  A console with more horsepower than a handheld you might hold with different regards in terms of appearance and how games should look.   Ratchet and Clank is a totally different ball of wax.   Just because Ratchet and Clank is a cartoon game doesn't mean it suddenly is Mario's equivalent in cartoon appearance.  Maybe, she feels that Ratchet and Clank is the right amount of Cartoony and Mario is too much.  I certainly would say in my opinion that R&C is less cartoony than SMG. (Even though both are cartoons).  Again, you can't prove this point.

4.)  People dislike games for different things all the time.  People complain about swearing in games. People complain about controls, appearance, etc.  What's your point?   The points she raises certainly exist in the game and while some people love them, some might absolutely hate them.  Thus making the opinion valid (Able to be questioned, but still valid).   There is enough 2D in the game for someone to be bothered by it obviously and I'm sure she isn't the only one saying it.     Just because she didn't do the routine ball wash of Super Mario Galaxy 2 doesn't mean she is biased.

'
Removing redundancies. Things like new levels(seriously?).  Every game has 'new levels'.   I'm talking on a legitimate sense.  These above are the 'improvements' to the Mario series in 14 years. 

- Linearity

- Star Bits

-Powerups

-Playable Characters

- Walking on 3D Surfaces

I would say a good portion of those features we have witnessed games add between sequels in the same generation a year or two apart.  14 years later and one of the big innovations is 'Collecting Star Bits?'.  Since when is Linearity something that is applauded?   You're making my case for me.

Dtewi, stop.

Walk away now.

Someone is wrong on the internet.

(Don't worry, I can keep my temper down enough to not get banned.)