Office-to-residential conversion: what kills deals in due diligence?

Three screens before anything else:

Floor plate depth — anything much past 90 feet window-to-window leaves you with dark bedrooms or donut corridors that destroy efficiency. Plumbing risers — office cores cluster wet stacks centrally; residential wants them distributed. Retrofitting risers through occupied-floor slabs is where budgets go to die. And the curtain wall — if it doesn't open and can't be cheaply modified, your operable-window requirement just bought you a new facade.

If a building passes those three, THEN look at the incentive math.