Well the riddle you're wrestling with is the classic tri conundrum. How to be good at everything.
I'm no expert but I can understand your problem and FWIW - here are a couple of "truths" that I've learnt and train by which might help you solve your riddle. I might be completely deluded but they help me. A race is almost never won on the swim, occasionally on the bike, mostly on the run - assuming that you're close enough to run down the fast bikers. Balance is the key.

1 x major workout per discipline per week. for me this currently means a 4km swim, 90 km bike and hour plus run. The other, smaller workouts fit in after this.
Space the major workouts so you get at least a day in between.
Intervals are a great way to train, particularly for the bike and swim. You can cut down a lot of riding/swim time but being structured and going harder on an interval program.
Swimming is the least likely to injure you via overtraining, followed by cycling with running the most likely. Once you can swim fast, you can kind of park swimming to a degree and then focus on the other disciplines while just keeping your swimming in tune.
Here is a program from a the 2010 35-40 KONA age group champ, Damien Angus from firstoffthebike.com - read about how he plays to his strengths: http://www.firstoffthebike.com/inter...s-and-training

Check the interesting comment at the bottom about the balance between bike and run: to run 20% of what you bike each week. I've heard this + swim 7.5 - 10 % as well. Thus a routine might be: bike 150km, run 30km, swim 7-10km

Any help?