I didn't cover the MO diagram of BF3 in my second-year course on MO theory.
This may be because there is a difference in the quality of student at a UK
and a Canadian University? I did briefly mention that CH4 is not sp^3 hybridized.
The MO of CH4 etc is covered in a 4th y course (organic prof).
BF3 may have been mentioned in a 3rd y inorg course (different instructor) we had
but we did away with that course and put in a course on materials.
In order to understand the MO diagram you have to be familiar with quantum theory,
and the Bohr model, wave functions and the SWE, the LCAO method, and symmetry.
Not three years of constant study but usually met in your third year of a BSc if at all.
The link to the "rant" ishttp://pubs.acs.org/doi/full/10.1021/ed100155c