Focus on combination of scientific issues and instrumentation. Remember that capabilities are more than the instruments alone. Emphasize Gemini's best attributes. Require performance that preserves Gemini's outstanding features. Duplicate capabilities can be justified by potential for scientific returns.
Telescopes have to be effective in worse than median conditions.
Consider Gemini in the context of other large telescopes. Each group was charged with developing a list of problems that they saw as important and addressable over the next ten years. For each problem, they were asked to list the required observations, the instrumental capabilities needed to make those observations, and some sort of benchmark for the capability. Merging the four lists produced the following list of desired future instrumental capabilities for Gemini. Note that the order represents some measure of the overall importance of the capability, although the sequence in which instruments are built may be determined by other factors.