Early on with GTD I made the mistake of treating the Weekly Review as a "catch up on my processing session". Sure enough, I tended not to finish the weekly review.
Now, I strive to stay caught up with the processing. My WR is on Friday morning, so Thursday before I go home I drop 15 minutes on plowing through accumulated meeting notes and other amusements. Then when my WR time comes up on Friday, I spend at most 10 minutes doing processing, then go straight into the reviewing, checking off things actually done, and updating my written view of projects & next actions so that they match reality.
You say you have a tendency to get balled up in 2-minute actions that then take longer than 2 minutes. I remember that David points out that 2 minutes is a good default, but if you have a leisurely afternoon, make it longer, and if you want to make sure you get through everything, crank it down as far as 30 seconds. That seems to be how I do my review in practice -- any next action that isn't "file" or "record this information in my address book" (those are 30-second tasks) simply gets recorded for later. Phone calls are DEFINITELY not a 2-minute action, neither is looking things up on web sites (my personal bane), etc.
As for processing dovetailing into organizing, I experience that too, but I don't see it as a problem to be solved. I see David's insistence on keeping these separate in GTD as something of a startup issue: when you're new and you don't have a familar organization system, it helps the learner to keep the two phases distinct. However, once you've got your system down cold, I don't see a necessary distinction between (eg) processing some meeting notes, realizing that there are a couple of next actions to be recorded, and creating a new project tree in my Life Balance outline to hold them. It flows very smoothly, and that's what I need.
Hope some of this helps,