Sightlines
If they cannot see each other, it is not a gathering
A centerpiece can win the photograph and lose the table. Height is not hospitality.
What this is
People came to see faces, a host, a vow, a toast. Anything taller than seated eye-line on the conversation axis is a claim against that job.
The usual failure
Tall florals, a sweetheart table that turns its back, pillars, a stage two-thirds of the room cannot see. Guests compensate by looking at their phones. That is a sightline report.
A reversible test
Sit in the worst seat. If you cannot see the person opposite or the thing the evening is organized around, lower or move one object. Paper mockups count.