The most important things I would like to see:
- ODE/OPCODE replaced with something better
- high quality shadow templates (PSSM,...) - We shouldn't be dependent on half-baked user contributions.
- scrap WED and MED (they are messed up beyond all hope) and concentrate 100% on GED - GED is a start but it only is 10% there yet.
The first two points shouldn't be very hard to do but considering Conitec's track record it probably will take 3 years.
You need custom tools to make your work easier.
That's why editors like the Unity one are fully scriptable.