Given that we just recently finished the Yomim Noraim I would like to express some thoughts about my experience.
I. Very few people pay attention to all of Chazaras Hashatz. It is simply too long with too many arcane and complicated piyutim.
There seem to be 4 groups of people
1. Those who actually pay attention to the whole chazaras hashatz, a very small minority
2. Those who try but can't focus for the whole time so they bring a sefer and look at it at various times
3. People who are bored and either fall asleep or daydream
4. People who keep themselves busy with various things (e.g. on Yom Kippur walk around with smelling salts), go in and out, etc.
I admit that I belong to group 2. I try to pay attention but I find it very difficult to stay focused on many of the piyutim etc.and always bring a sefer to look at it.
I don't have a solution for how to make the situation better, but I see with my own eyes that it is definitely a problem. If only a small percentage of the people in the shul are paying attention to Chazaras Hashatz then what is the point?
II. I like the idea of setting a fixed amount time (e.g. 15 minutes) for the silent shemoneh esrei. It makes it possible to pace your silent shemoneh esrei so that you can finish in time to hear chazaras hashatz (if you want), and if you daven a little quicker, you know exactly when chazaras hashatz will start so that you can go to the bathroom, learn something, whatever, knowing how much time you have.
III. No speeches. The davening is long enough and people have a hard enough time focusing on it, adding a speech is counterproductive. Davening on Rosh Hashana was almost 6 hours, to add a speech to that (especially along one) is too much. In addition, on Rosh Hashana many shuls announce that shofar blowing will not be before X AM so that the women know when to come. The speech has to be before shofar blowing because afterwords you can't be mafsik. Therefore, in my experience what happens is that the women come at X AM and the Rabbis is speaking and they need to wait who knows how long until the speech is over. if there is going to be a speech it should end exactly at X AM no matter when it started (even if it started 2 minutes before).