It depends on exactly what you're proposing about I1. The expectations of the ancient DNA are different if we're proposing something different about I1 than Paleolithic R1b proponents are proposing about R1b.
Those who say that R1b has been the dominant haplogroup in Western Europe since the end of the Ice Age are contradicted by the lack of R1b in Europe before the Chalcolithic. Even with the small number of ancient samples, it has gotten so severe already that the only way to explain it away now is to say that the samples systematically excluded populations that were likely to be R1b. That, though, seems unlikely, since the existence of I2a1a in the Neolithic samples shows that hunter-gather populations joined the Neolithic farmers to some degree, and it doesn't make much sense to suggest that populations who didn't take up farming ended up the largest after the Neolithic.
On the other hand, "conventional" predictions about I1 suggest that it was a minority North/Central European haplogroup that didn't really expand until toward the end of the Neolithic. If that's true, then we should expect it to be present in North/Central Europe during the Neolithic, but in very small amounts that are not all that likely to show up in the limited samples we have. The Danish samples that are supposed to come out at some point offer some promise, but even they're not a slam dunk.
If, however, we say that I1 was widespread in Europe by the beginning of the Neolithic, as Fire Haired does, then we have a problem.
