Expanding the cast of Lucky Star at an earlier stage
Success in the slice of life genre depends on one thing. It isn't the animation budget, the music production, the plot and setting, or even how funny it is. The key ingredient is the characters and their chemistry. And while that chemistry is present in Lucky Star, it isn't fully realized until the full cast is present later on. The solution itself is simple: bring the secondaries into the mix earlier.
The first half of the series works like this: Konata plays the boke (funny man) as the otaku to rule them all, inciting biting and comedic response from Kagami ala the tsukkomi (straight man). Sometimes Tsukasa or Miyuki are involved, in their own clumsy way provoking Konata into doing something outlandish. This style of Japanese stand-up comedy -- Manzai -- has been used often enough before and to great effect.
While it works here too, it gets really old far too quickly. There aren't any tender moments in the first half to balance out the hit-or-miss comedy like there are in Hidamari Sketch or Azumanga Daioh. And while those softer, more reflective moments could be used here, Lucky Star doesn't particularly need them. What it needs is the show's full cast.
From the warped mind of gaijin otaku Patricia Martin to the dojinshu artist who uses her own friends as material Tamura Hiyori, the secondary cast is stacked with potential humor. It took far too long to get them in a room together with Konata, but once they did it turned comic gold. Beyond that humor, they provide more relationships and different types of interactions.
The later episodes in which these characters appear are more balanced and overall feel better to me. Remember that the anime is an adaptation, meaning things can -- and should -- be changed for the sake of flow. Bringing in the cast earlier in the series is a realistic and easy to implement method of improving the anime adaptation as a whole.
1) ghostlightning
Very interesting point you have there. You called it right that it could have been changed for the sake of flow since the whole thing is not that linear anyway.
Also, since it isn't a plot-driven narrative, it won't suffer from having so many characters there at once, since they're there to add color and influence chemistry.