Software design is not really my wheelhouse so I can't comment meaningfully on that, but on the networking side I can very confidently say it was a poor architecture. You simply cannot assume that all of your clients are going to be both 1) non-malicious and 2) work exactly as you think they will.

Link saturation would be one of the first things that would come to mind in this situation, and at these speeds QoS would be trivial even for cheap consumer hardware.