If you read my post again: I did not say you said the games were crap. If i read your original post correctly, I thought you were talking about innovation, I was merely disagreeing with it and putting my opinion across that I believe there was enough innovation between each title not to be put with Splinter Cell / Need for Speed / Command and Conquer.
2 introduced iMuse which then went on to be used in many Lucasarts games after that, and is a system better than a lot of games have today. 2 didn't have Insult sword fighting from 1, or rhyming which came in 3. There really isn't anything similar to it in 2. If i remember correctly, 2 didn't go back to Monkey Island. Since you had higer res for 3 and 3d for 4, maybe that 2 had a different art style from 1 is also big enough of a change (yes, still 320x200, but oil painted backgrounds rather than Dpaint ones)
3 and 4 both changing the gui (both times new to the series, not adventure games as a whole)
Yes 4 did have insult arm wrestling at the start (it brought back a lot from 1, Melee Island, Carla and Otis..) but then also brought in Monkey Kombat which was new to the series.
Would I say they're really innovative? No.
Would I say each one is innovative enough to be separated from games such as Splinter Cell etc? Yep.