With a codebase the size that I am sure DDO is, there would have to be systems that are intricately intertwined with other parts of code that no-one working at Turbine now, really fully understands how the interaction works, or why it was coded that way to begin with, but they know that attempts to rewrite it have wasted many hours and failed miserably (or the code written ended up going toward some other system)
I can only imagine how many attempts have been made to rewrite sections of the code that have just resulted in many wasted hours and probably explains some of the weird things we see like the multitude of crafting systems in the game. I'm sure stuff like adding the force ritual to a cannith crafted weapon increasing the min level is not intended but the interactions involved are so convoluted, that no-one is game to try to fix it because of the possible ramifications and would also explain why the stone of change crafting system hasn't seen an update in so long.
I'm sure some of the developers working on DDO now probably have dreams/nightmares on how they would code certain sections of the game if they were making it now. I often wonder if there is a whiteboard/specification document somewhere outlining the games intended progression from 1 - 20 (if this was even in the original spec) and if so, how that compares with what the game actually looks like now.