The mechanism design lectures I've been watching have focused on the objective of maintaining performance guarantees in terms of either total surplus or total revenue/virtual surplus (while also paying attention to inventive compatibility guarantees and polynomial runtime guarantees).
How far away from this objective can a mechanism designer wander, and still use the discipline of mechanism design to formulate games? For example, can the mechanism designer care about some specific combination of surplus and revenue, or about minimizing the number of rounds an ascending auction is expected to finish in relative to revenue (maybe the auction venue charges by the hour), etc.? Can surplus optimization and revenue optimization (subject to incentive compatibility and polynomial runtime) be extended to cover the vast majority of real world design objectives for auctions and other mechanisms, and if not, does mechanism design have the tools to address other real world objectives, or is the field too limited by how new it is?