Opening preparation - therapeutic?

A couple of years ago I was playing in an annual BC-Washington chess match. My game has gone into a long and tiring endgame, but as I was walking around, waiting for my opponent to move, I overheard US master Marcel Milat analyzing his game against Alfred Pechisker. Marcel won as Black, after gaining a nice position out of the opening. He uttered one phrase that stuck to my mind: "I find studying theory to be therapeutic." I thought to myself. "Holy Crap, how does he do that, why do I always have a hard time learning opening theory, deciding on which line to pick for my repertoire, and even worse - during the game desperately trying to remember which move to play on move 10, while my master opponent is walking around, wondering what the heck I am thinking about."

The word "therapeutic" however stuck to my mind; I was wondering how to be like Marcel and calmly study opening theory, the same way I analyze my games and endgames (which I actually do find relaxing and pleasant). Marcel was well-known for great opening preparation when he lived in BC, so I realized that proper attitude is key to success. Several problems seem to have plagued my opening preparation in the last few years (aggravated by rarely playing in regular chess tournaments):
1) Getting tired of old openings after a disappointing game put doubt on a certain line (a crushing quick defeat or unpleasant pawn structure that drags on until endgame)
2) As a solution - trying to switch to new openings, but not having enough practice to learn them, having similar problems (or even worse) in the new openings. This is a known syndrome (giving up on old lines too easily), that leads to 'jumping', but it is sometimes hard to distinguish from just wanting to learn new middlegame structures.
3) In openings that I rarely encountered -  not even having any line prepared at all ("so what do I play here on move 7")
Somewhere around summer of this year, I realized that I if I want to take my chess openings a bit more seriously, I need to change my approach, which now consists of several points:
1) To NOT study new openings in replacement of what I already have.
2) To review and organize (in a database) all the lines that I have ever played - making my repertoire more formalized and concrete, so that over the board I don't have to decide between 3 lines that I have played before. Part of my problem was that I forgot the stuff I actually did kind of know 5-10 years ago, so it was definitely useful to review those old lines. Another source of frustration was having database files scattered all over my hard drive, in different database formats (some in Chessbase, some in Chess Assistant), making it really hard to figure out where to add new lines, or update existing ones. That had to be fixed for sure. Somewhere (in a database, on paper, etc) - there must be a tree of moves that constitute my response to every possible move, in a style to similar to Nunn's Chess Openings.
3) Fill the gaps I have in my repertoire (identify them first, and gradually - prepare some lines in response to openings I never played...)
4) To plan my other study (practice games on ICC or book reading, etc) around that formalized repertoire.
Thinking about it again - with a more conservative approach, I see how studying openings can be "therapeutic", since I would have a goal that I can gradually move forward to - a manageable opening repertoire that fits into my memory, but also fits my style. As Alex Yermolinsky said in "The Road to Chess Improvement", "Man gotta know his limitations", and definitely with playing 10 tournament games a year, it's hard to master King's Indian, Sveshnikov Sicilian, and Marshall attack from scratch all at once, so you have to make some choices; or else the number of possibilities one has to remember on every move can easily get out of control ...