I’m not sure if this is in the engine but if its not then this is a feature request. Blueprint Finite State Machines without animation. the Ability to make a blueprint that runs on a state machine with animation attached would be really useful! simple example: you have a door with 3 states, Open, Closed and Locked. while i understand that this can be done with basic blueprints, having a built in blueprint type for it would be Massive. this would allow you to very easily create a whole new range of behaviors that would be very complex without it. AI, Quest Systems, Dialog Systems, etc… imagine you could add a blueprint attached to a state of the state machine with all the normal tools of a blueprint except it was only active when in the parent state. you could make a dynamic quest system very easily. again i’m not sure if this is already in the engine but i thought id share it as i find this feature to be really enabling to a developer. i have an addon for unity that does something similar and its made my life a whole lot easier. combine that with blueprint and you have an amazing tool for development on your hands.
Behavior trees. It’s still experimental, so I haven’t used it yet, but I imagine that it could be used for things like door actors (Open, Closed, Locked, Broken) and lights (On, Off, Broken) as well as AI.
Right now I’m just making a super hacky blueprint AI “state” machine. I use the tick event and check a ton of bools, and send to a new “state” if any of those bools change. After I send out to a new “state” I trap out the bool so it doesn’t keep sending to that state.
You can use the switch node to switch on a “current state” variable. It’s not a lot more work than a dedicated state machine graph kind, although you need one switch per kind of event/input.
For visual simplicity, you could group the different event handlers in comment sections for each “state” although if you got it wrong nothing would tell you about that 
Behavior trees and animation state machines are very specific to animation and AI.
The OP (and me) wants something general.
Apparently in the years since this thread was created, there’s been a plug-in developed, but in my case the project is so long that I don’t dare to rely on plug-ins which can be abandoned and unsupported at any moment.
I wish Epic would have made a general solution instead of having their teams invent new special case UIs in isolation all the time (like Dataprep lately).