You don't see whoever assumes power in the interregnum would crack down heavily on the revolutionaries? Or an internal power struggle among the ruling elite?
Well, the crackdown is part of the "blood" part I referred earlier. But by 1905 the Czarist system simply had to reform or break down entirely, and the person of Nicholas II was among the main obstacles for a new Duma and Constitution, ideas that enjoyed widespread support among the emerging middle class and their representative parties.
So unlike in the earlier cases of regicide in Russia, the death of Nicholas II is likely to lead to the rise of the same strong ministers around Stolypin who came on top in the OTL post-1905 revolutionary struggles, and to same kind of reforms. The war had discredited the old power-brokers like Kuropatkin and Witte, and Stolypin and his colleagues were the only credible alternatives.
It would require extraordinary circumstances to avert the reforms and the rise of the new ministers, since the reforms were supported by such large segments of the population of the Empire, as well as key members of the old regime, and the new ministers were the only people who could bring them about. At least that is how the people in Russia saw the matter in 1905.
The key difference to OTL is that without Nicholas II, I fail to see how any of the possibe replacement Czars could conduct a similar determined "rollback" of power that Nicky did between 1905 and 1914.