Your still going to get a little bit of oil in the combustion chamber no matter what. Why? Because if the main bearings are oiled through lets say the gearbox oil (Bimota V-Due) all that's left is the rod bearings which aren't going to need a lot of oil. But you can now run oil ratios like a RX-7 wankel engine which are like in the 1000 range, maybe not that drastic but you get the point.
In the end, is the engine going to be cleaner? Yes. Is it going to be more efficient? Yes. Will it need less oil to run? That's a positive. Is it going to make more power? Now that depends. No one will know with out R&D, because you just can't assume these days, you need facts to back it up. To be honest I think a DI engine will work for motorcycles we just need someone to build the damn thing.