Manufacturers are going forward with Direct Injection because of the increasing demands for higher fuel mileage, from both the marketplace and governmental pressures. This push will continue regardless of whether DI leads to increased fuel dilution of engine oil, or not. Oils are always improving anyhow, to accommodate today's and tomorrow's engine operating conditions, and no doubt fuel dilution issues will continue to be a focus point for oil producers.
Whether DI will cause more fuel dilution, or whether fuel dilution automatically equals increased wear, is going to vary depending upon each individual application of that technology and that engine's operating conditions. And only time will tell.
Auto manufacturers can test this technology relentlessly in the lab and on the road, and I'm sure they have, but nothing can match the DI test that is ongoing right now. Several million vehicles running DI engines for a few years will be the ultimate test. Some manufacturers will pass that test with flying colors, and some will not, and who passes and fails won't necessarily be who we'd expect.
In the meantime, if I had a DI engine I would be inclined to use caution and change the oil on the severe use OCI schedule until I was completely satisfied that it was unnecessary.
DI is the next step in fuel delivery and in time I expect we'll see it in almost all daily driver type vehicles. As a late-adopter I'm looking forward to sitting back and observing how DI technology impacts engine life and what adjustments will be made. Pull up a chair, this is going to be interesting.