Question for my fellow professionals

I am looking at another fairly new over sized boiler. 456 square feet where 354 would have done. Convector system and I installed a vapor stat. Boiler is an atmospheric natural gas and is running at the low fire for the number of sections.
What would you tell the customer to do next?
I have my list. Replace clogged return, increase cross over trap speed, improve main vent and repair the one bad trap.