Its an annoying issue. Even more annoying trying to find a solution and reading everyone's drawn out examples on the matter.
How about that : No turn base combat. Real time 1 round = 6 seconds unless paused. Add a few more enemies, slightly lower HPs and VOILA! lol. Fast, dynamic, frantic, and strategic combat all in one! That would be so amazing.
The solution is simple. This game is based on D&D, not a FPS; it isn't supposed to be fast/frantic (you cannot have a fast/frantic pace and keep strategy, strategy takes time) it is supposed to be steady/strategic.
Simple solution: "... force turn-by-turn limitations globally, even those out of combat. ..." "... party members out of combat would all act on the same turn as the one who started combat, until they roll initiative themselves, and non-party-non-combatants would act on the same turn as the person with the highest initiative (or would act on a predetermined, never changing, global base initiative like 10 or something). ..."