I am sure they will promise them at e3,and I doubt they will make a difference. For every exclusive xb1 game, Sony can counter with its own. And the exclusive play is a long run, save for a megaton, like Microsoft buying Rockstar, it will help but not solve the xb1 problems.
What XB1 problems? Sony lunched PS3 one year after XB360 at higher price with worse multiplatform games (compare to XB360) and lower quality online services/support in first 3-4 years of last generation and they didn't use any secret sauce/feature to make PS3 what it is today but making their services/tools better, bringing more games and reducing the price.
XB1 price is 100$ higher than PS4 and it's its only problem. Is it possible for every PS4 to be a Dev-kit? Is it possible for PS4 to have Universal app between windows and a wide range of phones with same OS? If Microsoft make it's own Xbox ecosystem (multiplatform Steam like service) on XB1/PC/mobile for digital games and offer gamers digital games that can be played on PC/XB1/mobile with one time purchase, what can Sony do to counter this? They have DX12, they have Universal Windows apps, they have mobile/windows/XB1 and hardware/local solution to do this. What can stop Microsoft from doing such a thing?
You are looking at XB1 like a weaker PS4 while potentially it could be a totally different beast.