Hi Istvan,
In my opinion SPO is not difficult to manage and can reduce development as well as operating costs. I suggest to carefully define which partitioning characteristics to define and standardize. Furthermore, only partition if there is a clear need to do so.
Re. scheduling you are free to define any kind of parallel processing in your process chains. SPO does not mean that you have to run all DTPs in parallel. You can also choose to run them sequentially or maximum 2 parallel processes at the same time. Although SPO can generate process chains for you, it is not mandatory to generate and use them. If you decide to generate them using SPO, you can always modify them.
Last but not least, please have a look at my blog series re. Pattern-based Partitioning using the SPO BAdI. You can access the blogs via Pattern-based Partitioning using the SPO BAdI - Part 1: Introduction.
Best regards,
Sander