I am not about to commence serious IFR flying but would like to be able to fly on instruments in cloud if the weather deteriorates and also navigate using NDBs and VORs more effectively than I am currently able.
But that IS serious IFR flying! What more would you need to add to make it truly serious? Flying inverted? (The USAF apparently teach their pilots to do aerobatics in IMC though I'm not sure what the point is).
Flying in clouds is really serious stuff. Just holding a heading and altitude takes a lot of practice. Doing that AND all the other fiddling around that accompanies IFR flight (talking to ATC, twiddling radios and navaids, monitoring the engine...) takes REAL concentration.
Approaches are a challenge too. There's no such thing as "just being able to fly an ILS in case I need to". You need to practice constantly. I fly with an instructor about six times a year (most recently last night), and on my own in actual when I can, and I think that is really about the minimum. (And as it happens the FAA pretty much agrees, if you look at the currency requirements).
That said, instrument flying is also a lot of fun in a challenge-y sort of way, and I would strongly recommend doing it. And of course if you do it to a sufficient level of competence and stay current, then it may well save your life too, which is never a bad thing.
n5296s