My group has adopted a house rule for initiative in Pathfinder that goes like:
All players roll individual init on first round as normal, but the DM only rolls a single Initiative die for the baddies
All PCs that beat the DM roll get to take a turn
Then we just alternate between sides starting with the monsters. When your side is acting, players can act in any order. As mentioned above, this keeps everyone involved in the combat and actually speeds things up quite a bit as players do not tune out waiting until their turn, and then take extra time absorbing the situation again when it is there turn.
Interesting, I like this. It kind of blends the WFRP 3rd edition system with old school rules in a simple way (which is what I want).
How you deal with interrupts to spell casters? In a system like this the casters can't really be interrupted during casting as they will know if they have been hit or not that round. In one of the systems, I believe I read it in Labyrinth Lord, the two sides declare their actions and then initiative is rolled each round
but it's done for the whole side (so it's still quick). Thus if a caster states they are casting a spell but their side loses initiative and an NPC attacks, they can be interrupted in mid-cast.
Can your system allow for this?
Edit: Actually I think Pathfinder just adds a penalty to the cast if you are being attacked so I probably answered that myself.