There are some design and material improvements that would go a long way to increasing the useful life of the grill.  Where possible steel components (specifically fasteners , brackets, shield covers, frame structure) should be replaced with aluminum or stainless steel (corrosion resistant materials).  There are some components that will last forever, but there are some simple parts that corrode prematurely and need upgrading (simple example are the screws that hold the side burner together).