When you look through forums, people often criticise Nintendo's games for not being innovative enough, especially The Legend of Zelda: The Wind Waker and Super Mario Sunshine. But I wonder, what did they expect?
Let's look back to the "good old times", where everybody agreed that Nintendo was a top-of-the-line developer, before all this talk about "the giant stumbling", etc appeared.
First, Super Mario Bros. I will consider SMB1-3, SMW1-2, SM64 and SMS to be part of this series for this purpose.
SMB1: The first of the series. Not much to be said about its evolution, since it is the first in this chain of evolution
.
SMB2: Radically different gameplay. Since almost no ideas from this game made it into later games, we can assume the innovation here wasn't desired.
SMB3: Basically SMB1 with more items, levels, enemies, etc. A sequel.
SMW1: Still a lot like SMB1 and 3, new powerups and the introduction of Yoshi. While this changed gameplay quite a bit again, it didn't change much more than, say, the different weapons in different Quake or Unreal iterations.
SMW2: Could be considered a spinoff. The gameplay was fundamentally different from the main series. Like SMB2, the changes in this game never made it into the main series.
SM64*: While I have never played it, I assume it was a rather huge leap forward. However, this game did the change from 2d to 3d, which naturally offers MUCH different gameplay.
SMS: Not much innovation except for new items. Since the 3d-transition could not be repeated, this game did not differ from its predecessor as much as the latter from its.
If we don't count spinoffs, the changes from game to game are rarely more than more items. While Sunshine didn't deliver as many items as, say, SMB3, going overkill is never good. Did SMS need a boatload of additional items? No, it works fine with the current ones.
Now lets look at the other Series mentioned, Legend of Zelda:
LoZ1*: Well, the first game. Defined Zelda-gameplay, etc.
LA*: I haven't played it, but it looks like a large departure from the previous game. However, this style doesn't seem to have carried over into later titles.
Links Awakening: Basically still LoZ with new levels, maybe additional items.
LttP: Still LoZ with added items and better graphics.
OOT: First 3d game. Of course a lot changed due to the change of perspective.
MM*: Dunno, but it seems to be mostly like OOT with new levels and maybe more items.
WW: Basically OOT with new levels and items, the addition of sailing didn't add a lot to the game and was completely irrelevant in the actual dungeons.
For comparison, the Metroid series did not get any "more of the same" comments:
Metroid*: Defined the gameplay, blah, blah, blah.
Metroid 2*: Doesn't seem too different from the first one. Sure, new enemies, maybe new items, etc.
Super Metroid: New items, levels, etc.
Metroid Prime: Switch to 3d, radically different gameplay.
(note: * marks games I haven't played)
Notice a pattern? The big, innovative titles all were the ones that changed the series from 2d to 3d. Of course that brings a difference in gameplay. The only thing that has changed from back then to now is N's willingness to make the second game in each series a spinoff title.
p.s.: The decrease of writing skill through this post can be attributed to increasing tiredness.