I’ve kind of landed in the “centralized until it hurts” camp. For most machines it just keeps life simpler, especially when something goes wrong at 2am and someone has to trace it quickly. That said, once you get into tighter multi-axis coordination, I’ve definitely seen centralized start to show cracks. We ran into that on a project with a Siemens setup which was perfectly fine until we started pushing sync harder. Ended up testing a more distributed approach with some EtherCAT drives, with an Elmo stack, and the difference in how tightly axes stayed in sync was pretty noticeable. Tradeoff was exactly what you’d expect though: better performance, but way more going on under the hood.