Evaluate this implementation plan for a software feature.

The plan was created from a specification. Analyze:

1. ARCHITECTURE DECISIONS
   - Are the technology choices appropriate for the requirements?
   - Is the architecture over-engineered or under-engineered?
   - Are there simpler alternatives that weren't considered?

2. RISK ASSESSMENT
   - What could go wrong with this approach?
   - Scalability concerns?
   - Security vulnerabilities?
   - Maintenance burden?

3. SPEC ALIGNMENT
   - Does the plan actually address all spec requirements?
   - Any requirements that got lost or misinterpreted?
   - Does the plan introduce scope not in the spec?

4. IMPLEMENTATION CONCERNS
   - Are there tricky parts that need more detail?
   - Missing error handling or edge cases?
   - Testing strategy adequate?

For each issue, mark as BLOCKER (must fix) or SUGGESTION (nice to have).
Be specific. Quote the plan when identifying issues.
Suggest concrete alternatives where you see problems.
