It's always interesting to hear ideas for features, and we very much appreciate this kind of feedback. We will make a note of your suggestions.
In general, we have more ideas than we have time to implement them, so it's always critical to get an idea for why a particular feature is important, in order to be able to prioritize it properly. Otherwise it becomes a feature just for the sake of the feature, without providing real value.
You have provided a good argument for the Methfessel-Paxton smearing; however, I also note that it can produce negative occupation values (unphysical!) which cause problems e.g. for visualizing the density of states. So, as always, one must tread lightly in these territories