-FIFA (2003 was the last great FIFA game)
-Advance Wars (I want to think that it DoR was only a minor slip and won't happen again, if next game is back to Dual Strike quality I'll forgive that mishap)
-Age of Empires (never again like II, nor Mythology nor III had the magic)
-Need For Speed (self explanatory)
-Guitar Hero (WT inferior to III, which in turn was inferior to II)
-Pokemon (after the superb Gold, and the good Sapphire, it's now boring. I can't play the same game over and over...plus, I can't understand why Gold had more things than the following games)

Crash Bandicoot doesn't count. Its because Naughty Dog stopped making it, not because it lost the plot.

I don't have any new ones to add that haven't been said.

Sonic, Spyro, Crash Banicoot

Thank you! No one else seemed to recognise that DoR was a step backwards.

I have wondered the same thing. Nintendo really has been lazy with pokemon series after the gold.

Halo and Silent Hill (such a pity too) are two that went south for me. Halo for the SP, which I felt just went to pieces, Silent Hill for losing its focus with four (which was still good in places) and then making the huge mistake of handing the franchise to Western developers (who in my opinion could only copy not create the style needed to make a SH title come alive).

I'm confused. Am I misunderstanding the title of "plot" meaning it's story and not a general drop in quality, or is half the topic missing the point by concentrating on games that were always devoid of plot? If it's how I see it, I don't get how Tony Hawk, Crash Bandicoot, Super Mario, Winning Eleven, Need for Speed, Guitar Hero, Dance Dance Revolution, etc. have lost the plot when they never really had any to begin with.

Halo

I took it to mean either - e.g. some games have lost the plot in terms of gameplay or focus on what made them appealing (Need for Spped, Crash Bandicoot) while others lost the plot more in terms of focus on story/style that made them appeal in the first place (Silent Hill being one in this category for me).

Thinking about it for me personally the biggest loss of plot was Deus Ex to Deux Ex 2 - that was such a drop in quality, plot and gameplay as to be stupendous.

Tony Hawk
Need for Speed
Crash
Spyro