The only real downside I see to this is that the rules would end up in an awkward order for reading the ruleset. Could you explicitly specify that “Definitions {I}” should be placed immediately before “Teams and Targets {I}”, rather than at the bottom of the ruleset?

Hmm, but the Ruleset already has the Appendix and its term definitions as the last major section.

I guess it depends on whether we want players to read the definitions (early is better) or memorise/guess them (later is better). The core rules and appendix are arranged like that: rules that rarely come up, and obvious definitions, are at the end in the appendix, whereas important rules are at the start in the core rules.