Say that for whatever reason, the British decide to not only shell the GPO - but to storm it on the 28th of April 1916. A good deal of the Irish Republicans are killed during the brutal assault and upon surrendering, another large chunk is summarily executed on the spot. All the remaining survivors are then tried and sentenced to death for treason against the Crown, whilst London declares martial law throughout the entirity of County Dublin.
In the aftermath of this bloodier end to the Easter Rising, what happens now?