You seem to have forgotten the bad problems with issue 1 and the good of options 2 and 3.

1. If you have 1e6 rows already, and decide to introduce a new column, that's 1e6 null entries you have to create. It takes up space depending on the implementation.

If your table is thick, it may be a sign of poor organization. BUU suggested 2 tables, 1 for required, 1 for unrequired. It could be grouped even further. 1 for primary info, 1 for say, addresses information (if it is some of the data) and so forth...

2. It's probably negligible on what's being done. If you want to update all data, yes, it's slow. If you want to select, it may not be bad. It all depends on the frequency of operations.

And tell me, what database IS intuitive? W/o an ERD, looking at a db is a pain unless someone explains things.