The Ragusa node should be abolished and its provices added to the Venice, Wien, and Constantinople nodes; and the Krakow node should take some provinces from the Wien and Constantinople nodes to prevent them from becoming too big.
No need for such a drastic change. Just cut the Ragusa -> Wien link, and Ragusa will be fine.
Better yet, the devs could take a long hard look at the caravan power system, and ask themselves if it really makes sense for the HRE Kleinstaaterei to absolutely swamp the major powers wherever there's an inland trade link (sometimes including links that are nowhere near Germany). The unicorn puke trade power pie chart in the OP is a classic example of how this works out in practice.