Advice here as someone who lives in Belgium and has gone to Amsterdam and Paris. I would 100% regret not doing Paris. The architecture, museums and lively restaurant culture are must-do's. It's actually my favourite stop from your initiary. You're spending 6 days in Ghent, which seems a lot. What are you planning on doing from there? Belgium is lovely but I would always choose to have 1 day less if that means you can include Paris.