The issues I can see revolve around getting the same power out of the same size/weight engine reliably and inexpensively with a gasser as with a modern common-rail turbodiesel.
A modern EFI gasoline engine is pretty close to the same efficiency in HP-hr/lb as a current Tier 4 diesel. Gasoline engines can be built just as heavy as diesel engines and have a similar lifespan. Off-road gasoline engines have minimal emissions requirements, and even if they had to meet on-road emissions, those are still much simpler and less expensive than those of a Tier 4 diesel. At least regular 87 octane gasoline is also noticeably less expensive than diesel so your costs per HP-hr would be lower with regular gasoline if it could be done.
A naturally-aspirated gasoline engine running on 87 octane makes only a little more power (about 15% or so) at the same RPM than a naturally-aspirated diesel of the same displacement. The issue is that a highly-tuned four-valve multiple-turbocharged and intercooled/aftercooled diesel can make twice the HP/displacement as it would naturally-aspirated, so you would either need a much larger naturally-aspirated gasoline engine to make the same power or add forced aspiration to the gasser. Adding forced aspiration would either bring direct injection into the mix (which brings extra cost and some reliability issues) in order to continue to run 87 octane gasoline or you would need to run a much higher octane fuel to avoid needing direct injection. The limited market for turbocharged heavy duty non-diesel engines with similar power densities as the highly tuned turbodiesels is solidly in the "higher octane fuel" camp as they run on 106 octane propane or 120 octane methane. All of the industrial engines I've come across that run on gasoline are naturally-aspirated.
