For me, I require a stable alt mode that will sit flat and won't shift under the pressure of normal handling. It must not be floppy. For this reason I do not require waist swivels, as those often result in an unstable chassis for the vehicle mode. Transformations must be smooth and refrain from having parts crash into each other. The more motion, the better, unless it becomes a fiddly mess that is hard to handle. I enjoy clever uses and reuses of parts between modes. The robot mode must have good legs. Legs define the posture of the figure and if they are not sufficiently poseable, if the feet do not provide good balance or if the legs are not pleasing to the eye, then the figure is a flop. In the same vein as posture, waist swivels are nice, but if the figure does not also have a waist tilt, then they do not add very much to the poseability. I typically find that a properly jointed set of legs can make up for the lack of a waist swivel. While poseable arms are nice, poseable hands are better. Where the elbow is rarely matters for the quality of a pose, it's where the hand is and what it is doing. That is where the eye will be, that is what is important. Even arms with somewhat poor articulation can get the hand where it needs to go. What about you guys? What are your requirements for a good figure? What things are most important to you?