Systematic Outcomes Analysis is comprehensive rather than complex. The overall concepts in it are no more complex that the concepts you would have to deal with in something like basic accounting. Part of the reason that people have had problems with outcomes systems in the past is that they have wanted overly simple solutions and ended up with ones which generate problems because they are actually too simplistic.
Since Systematic Outcomes Analysis integrates strategy, outcomes, monitoring, accountability, evaluation, economic analysis, reporting, contracting, evidence-based practice etc, it obviously has to cover a considerable amount of material. If you do not currently have a need for parts of the system, you simply do not have to do them. Many people just start off using the approach to build outcomes models and develop strategic priorities.
However, following the Systematic Outcomes Analysis approach gives you the assurance that if, as usually happens in life, you are asked to, or decide to, move into other areas, it's very easy to do so. For example, say you have your outcomes and strategy but then decide you need indicators - no problem (building blocks 3 & 4); say you need to do something about evaluation - no problem (building blocks 5-8); or say you need to think about contracting - no problem (building block 9).
Doing Systematic Outcomes Analysis certainly takes time. However, you can work away on it over a number of years. The facts of the matter are that if you want to do certain things (e.g. indicator monitoring, evaluation etc) you will have to put in the time. By spending your time progressively developing a Systematic Outcomes Analysis model, you know that all of the different elements are integrated, you avoid duplication of effort and you know that the system as a whole will continue working for you in an integrated way.