High priority and low impact can and should be quickly fixed whereas low priority and high impact will end up lower on the list. With this in mind a "ranking" can be determined using the priority and impact fields (similar to the risk score in the Procon plugin).
Priority scores:
High
Medium
Low
Impact score:
LowMedium
High
Ranking = Priority score + Impact score - 1
Examples:
1 = High priority + Low impact
2 =
High priority + Medium impact
2 = ...