Er...It wasn't that complicated a ritual. He got his chain broken and only had three options. 1) Become a shinigami again. 2) Become a hollow. 3) None of the above, I'll become a vizard. You can obviously see which one he chose.
And I'm not saying it's something trivial either. "Oh, got my chain and soul sleep broken? No problem, I'll head over to 4th and 12th to spend a couple of weeks/months in painful rehab. If I survive long enough to get there." Remember, to perform senka you need to stab THROUGH a persons chest and lower chest/stomach area. Hell...Byakuya didn't even expect Ichigo to live after the senka hit. In other words, it makes one hell of a cool looking killing blow or could be used for power-loss plot as well.