First, let me be clear once more that my observation was not aimed at “mutual consultation” approach as Quran advocates. My observation need be read with “fairy tale” stuff. The foremost problem that I see with people coming together and deciding something for themselves is that they are divided in numerous sects. Sects by vary nature don’t lend themselves to constructive approach. Constructive approach regarding moon sighting is beset by the approach and mindset influenced by hadith they bring on the table. Despite, your observation of ICNA or ISNA whoever, the fact remains that Muslims remain divided as ever. Even groups and factions are prevailing within each mosque what to speak of the nation as a whole.
Second, “For those who can go through 'Saum' only with hardship” in 2:184 is NOT referring to the sick already mentioned therein. Rather, it is a third category by itself that covers any and all who though can do fasting but with difficulty. This category may include breast feeding moms, old people, people who are doing jobs which involve extraordinary hardships, people flying high performance planes, so on and so forth. The purpose is obviously to cover any and all situations beyond the first two categories.