I've reviewed a lot of junior/mid product designer portfolios and interview breakdowns, and the same 4 gaps show up over and over — rarely visual craft, almost always process:

1. "Why" before "what." Candidates jump straight to screens. Interviewers want to hear the problem framing first — who's the user, what's the constraint, why does this solution beat the alternatives you considered.

2. No evidence of iteration. One clean final screen tells me nothing. Show the messy middle — the version that didn't work and why you changed it. That's where the actual thinking lives.

3. Prototyping fluency gaps. Static Figma comps are fine, but if you can't quickly mock an interactive flow to test a hypothesis, you look slower than designers who can.

4. Weak product thinking under pressure. "How would you improve X app" questions expose this fast — jumping to UI fixes instead of asking what metric you're actually trying to move.

The uncomfortable part: most designers don't know which of these 4 they're weak in until they're in the interview and it's too late.

That gap is exactly why I built a self-assessment tool for product designers — it scores you across these 4 areas (UX process, visual craft, prototyping, product thinking) before you walk into the room, not during. If you're job hunting right now, worth 20 minutes to find your blind spot early.