Very easy to fix both Castrums and no need to rework them:
Main issue is what - time waste for older characters. Time waste is approximately 2x to 3x. Lets be generous and say 3x. So we multiply all rewards there by 3x, add group lock for all cutscenes (like the one on dungeon start) and add agressive downscaling to ilvl 42-50 for matched parties (random DF essentially). So one fixed run would count exactly like 3 speedruns, have same rewards and same time to complete. Also block votekick for these 2 duties and add RMT-like ability report aggressive guys from chat.
That's like 1 weeks work for two developers and 1 QA. Only apparently SE is not interested at all in fixing older content, especially with addition of MSQ skip potions. What is the point of fixing stuff that is intended to be skipped.