Answer
The gap that shows up most often in AS400 recovery plans is external dependency mapping. A restored system that cannot reach a payment processor, an EDI trading partner, a licensed third-party API, or a print or fax gateway is not actually back in production, even though every internal application is running. Buyers should ask whether the platform, or the surrounding documentation practice it supports, tracks these outside connections explicitly, along with who at each third party needs to be contacted during a real event.
Decision ownership is the other piece that plans routinely skip. A runbook that says to restart Db2 for i, bring up subsystems, and validate applications, without naming who has authority to declare the recovery complete, who approves a rollback if something goes wrong, and who communicates status to the business, will stall at the first ambiguous moment. Buyers should look for software that supports assigning named owners to specific steps and tracks whether each step was actually completed, rather than treating the plan as a static document. A plan that only lives in a PDF on a file share is effectively unowned, no matter how thorough it looked when it was written.