I know that there is a post similar to this in the S7 forum, but I believe everyone will agree that it's not really that much of a spoiler, and I'd like to get some feedback but the S7 forums seem to be a little apathetic - so here we go!
The mentioned post is about the usage of "breaking the fourth wall" in Season 7. Malcolm simply doesn't use his trademark "talking to the camera/audience" as much in the last season, and many fans seem to be disappointed by this.
I would like to present the opposite argument that this lack of direct camera dialogue is a good thing, and was pivotal to Malcolm's and the show's development into Season 7. Not only has the show been just as much about the whole family - if not moreso about the whole family - than Malcolm, in S7, but this lack of Malcolm soliloquy is symbolic of the boys' (and the plot's) maturity as we entered the final stretch. Malcolm seems to be becoming more and more accepting of his life, his future, and his family - and this is reflected in fewer family conflicts, more serious subject matter, and a less cynical Malcolm that we really started seeing after "Jessica Stays Over".
Shortly, Malcolm saving his trademark addresses for only the most resounding or funny moments, instead of every time his family "disfunction" needed to be focused on, is directly reflective of his changing character and the changing tone of the show. No longer are Malcolm or the show in general about "that wacky family" - it becomes a much more mature and measured tale of life, society and purpose. Malcolm no longer needs to break the fourth wall because his audience is experiencing his new view of life just as he is. From "Health Insurance" to "Malcolm Defends Rees" to "Hal Grieves", S7 in its entirety acts as a conclusion to the topical and intellectual development of the prior seasons.
I would like to present the opposite argument that this lack of direct camera dialogue is a good thing, and was pivotal to Malcolm's and the show's development into Season 7. Not only has the show been just as much about the whole family - if not moreso about the whole family - than Malcolm, in S7, but this lack of Malcolm soliloquy is symbolic of the boys' (and the plot's) maturity as we entered the final stretch.
I think this is a very good point and explanation. I felt I could relate less to Malcolm during the later seasons, which may be due, in retrospect, to the lack of direct address of the audience.
I also felt that his emotions were more limited, but that was mainly due to Season 6. It's true that the family dynamic changed, Malcolm standing up to Lois more, Lois alternating between letting her rage become completely irrational and potentially dangerous (A.A. and Lois Strikes Back) to being far more understanding of her sons and changing her behaviour towards them (Mono).
All the people are so happy now, their heads are caving in.
I'm glad they are a snowman with protective rubber skin.
I think that the fewer amount of Soliloquies in S7 and later series was not a directorial or written decision, rather, I feel the reason there were more of them in earlier seasons was to make to show flow better but as the child actors began to develop into more experience and believable character actors the show had less need to explain the emotions shown (I think the improvement of acting is best shown in Erik Per Sullivan's playing of Dewey, if you compare his performance in Reese vs. Stevie to his acting in the first three seasons the difference shown is astonishing.) Also the quality of writing improved, as earlier on Malcolm had to "set up" the story of the episode my telling the audience what is happening, later series flowed into the story with the need of a Sedge-way (This is not unique to MITM, as it normally happens in the Cold Opener, but as MITM chooses to go without this luxury, the best option is the soliloquies.) In later series the asides and soliloquies became redundant, but they were kept in for consistency.