Engine was Crystal Tools and it's biggest problem company wide was simple. Too many programmers and projects in the same development period, trying to adapt the same engine to the needs of their project. It was a tool programmers nightmare and caused the engine to be more limited, when one of original goals was not to have an engine as restrictive as XI's was.
This is why SE developed the Luminous Engine. Being easier to program for single or multi-platform, tailor to a specific project, and also supports the DX11 API for PC.