The over-emphasis placed on the Battle of Helm's Deep (how many times in the build-up is the battle being referred to as a lost cause? That the heroes have no chance of winning? And did we really have to see little six-year-old boys being armed and armored? Once again, the hammer of melodrama comes crashing down upon our heads.)
But, honestly, was this really a negative aspect?
I obviously respect your opinion, but I would personally view things in the opposite way.
The dramatisation and the climax (as in an ascension) in the construction of the film's plot was almost perfect and complete, intended as starting with a general negative situation, explaining contexts and developing characters, and, in the final step, the awaited and longed resolving battle, in which either the Good or the Evil must prevail.
I honestly think that this was exactly the film's strong and solid quality.
As other ones have already pointed out, both FOTR and ROTK kind of lacked this completeness in their own plot, but mainly due to 'physiological' reasons, deep in their very essence.
The first film was in fact the prelude of everything, with a mythical and fairytale-like essence, like Adamin wrote; the only prominent battle between Good and Evil is the one between Gandalf and the Balrog, but it wasn't definitely something expected nor was it constructed throughout the plot.
ROTK was the epilogue of the holistic picture; on the other hand, we could say that the plot was way too much (intentionally, obviously, according to the film's characteristics) constructed and planned, and that the initial phase of 'development' of settings and characters was not really accomplished because not necessary.
Therefore, I believe we could regard the second film as the most balanced regarding these aspects.
As if, as I wrote above, it dealt with a story in the story, a parenthesis of Rohan related to Middle Earth's events, but at the same time
complete in its own development and existence