1/2 hp and double damage goes a long way to speeding up combat. As you get the hang of what your party can do, you can continue to modify things further. If you simply double all damage output you'll likely kill of the party really quick, particularly if you double aura damage on monsters.
A problem with 1/2 hp on all monsters is that some particularly fun creatures will die before they can accomplish much of anything. This was especially true in my campaign where we have two strikers teaming up to spike.
I'd recommend running solo monsters with their existing damage outputs, but run two of them with HP = to their bloodied values. This works very well for most solo creatures and helps against the boring 4-5 round lockdowns that occur. Again, this will be a tweaking process as some dragons have very mean breath weapons and doubling them up can lead to PC's lockdowns as well. Consider scaling back the conditions as necessary. For example, the first use of a dragons breath can immobilize/stun, as can the bloodied use of it. However, every refreshed use of the breath will only slow/dazed.
A problem with 1/2 hp on all monsters is that some particularly fun creatures will die before they can accomplish much of anything. This was especially true in my campaign where we have two strikers teaming up to spike.
I'd recommend running solo monsters with their existing damage outputs, but run two of them with HP = to their bloodied values. This works very well for most solo creatures and helps against the boring 4-5 round lockdowns that occur. Again, this will be a tweaking process as some dragons have very mean breath weapons and doubling them up can lead to PC's lockdowns as well. Consider scaling back the conditions as necessary. For example, the first use of a dragons breath can immobilize/stun, as can the bloodied use of it. However, every refreshed use of the breath will only slow/dazed.