You identified the main problems very well cofcorpse, the rest it's just philosophical discussions
No you are wrong. TOO is HARM as a sensor mode, it uses the RWR for nothing. a/c RWR antennas have fan beam radiation patterns and don't resolve well in elevation, whilst using comparison methods (in amplitude, phase, doppler difference etc.) for providing an acceptable azimuth solution. Only most advanced systems (e.g. ESM) with interpherometers can give *some* elevation info, normally with way less accuracy that in azimuth.
The cool thing about the HARM though is that is equipped with a dish antenna on a gimbal, with a relatively thin pencil beam radiation pattern. The good thing about this config is that it provides same good (or bad) accuracy in all angles; the bad thing is that it needs to sweep in elevation and azimuth mechanically to provide a picture, which is time consuming.