From what I understand, talking to people who are actually involved in the design process or who have at least insider knowledge, yes, there will no doubt more than likely be actiony/arcade sequences involved in the new King's Quest game. Then again, there are several classic Sierra adventure games, such as the Space Quest games, Manhunter games, The Black Cauldron, Leisure Suit Larry 3, Codename: Iceman, etc. that all had at least one arcade sequence in them, many of which were NOT skippable (especially if you want to get full points). You could even argue that climbing the beanstalk or going down the mountain path in King's Quest I and III, respectively, are those games' versions of arcade sequences. At least in the sense that they require some fancy fingerwork.
It seems to me that as a whole, the adventure genre in the past 20 years or so has moved into a more action-focused nature. This is not necessarily a *bad* thing, but at the same time, I can understand why a lot of people who prefer the classic, original gameplay to dislike it. I think that this game will have some departure from the overall feel of the series, but then again, so did Mask of Eternity. Space Quest: Incinerations is actually a perfect example. Chris Ushko did an amazing job with a very awesome, traditional adventure game, but I was a bit concerned by the screenshots and what I saw when the game was still in production, as I was thinking it was moreso an action/shooter game. While it does have a few arcade sequences, it's nothing out of the line for Space Quest, which as I mentioned, is known for its arcade sequences in the series.
I will say that I did not notice any evidence of a health bar/life system in the new King's Quest game, something that is quite common in most action/platform games, which again makes me hold out that it will still have a more traditional approach to adventure gameplay. Yes, there may be jumping involved, but still, you can have a jumping element in a game (including a traditional adventure game) with it still being a traditional adventure. In fact, the idea that you can jump opens up the world even more, as it allows you to explore more, not less, as it now adds up and down as opposed to just where the path leads. Take a game like Xenogears, which is a very traditional Japanese RPG. It's not in any way an action RPG, but yet it has a jumping element, something which I have not seen in any other traditional Japanese RPG (and while leading to some frustrating jumping dungeons, at the same time, allowed for some fun alternatives to traditional RPG gameplay).
To me an adventure game has to have three main points: Focus on plot/character development; exploration; and puzzle solving. If a game focuses on all three of those points, it fits the book in some way of an adventure game. For it to be considered an action-adventure, there must be elements of an action-game involved, such as a health meter, battles/bosses, etc. I saw nothing like that from the trailer itself. Yes, you see Graham with a loaded bow and arrow aiming at something, but it's unclear what his purpose is in doing this, nor is there evidence that it's a Zelda type of bow-and-arrow battle.
I realize that my opinions are only my opinions, and I also realize that not everyone is going to share them, and I think that's totally cool. As long as we try to understand each other's opinions and see where others are coming from, then we can appreciate the differences which make up this awesome community.

In the end, what I see mostly makes up an adventure game, and even if it does have more action elements involved, as long as it has an involved and detailed storyline, I'm probably going to like it. For me, at least, story is the MOST important part of playing a game, and I'm looking forward to seeing what fascinating stories The Odd Gentlemen will whisk me away to!
Talk to you later!
JDHJANUS
Josh