Our group has fallen into a consistent pattern with initiative in a way that doesn't break the system at all, but which has turned things less dynamic.
We have 4 heroes. It goes: 3 heroes act, they hand initiative to the GM, I do all the GM actions, then the last hero goes. The "dynamic" part is usually just choosing which hero goes 1st and last. Even when I do the NPCs, I often just do them "scene tracker, then NPCs from top of the list to the bottom." I need to shake things up in a more interesting way.
Question: Do you ever interrupt your list NPC actors to let a player act?
On the one hand, I did that when I ran the starter kit and it usually made things easier for the heroes. They didn't have to endure all the enemy attacks before changing up the situation. On the other hand, it means I could re-capture initiative and go last to let villains go first next turn. But if I do that, it seems like a jerk GM thing to do, especially when I have more than 4 actors to choose from and I can guarantee this. (My players almost always win, but they're not walking over the opposition, so it's not like I have to step uo the difficulty necessarily.)
How do you decide this in your games? Do you find yourself in a similar pattern to mine? Do you pretty much insure some villain always go first? Do you really make it situational, in which case do the players take advantage of that in a game sense (i.e., "Ha! He let us have initiative; let's make sure we all act now.")?