I'm gonna give flowcharts a good try once the next beta drops that (presumably) fixes the crashes. I am arguing a little bit in the dark here because I have not yet actually build anything from the ground up or really at all.
I have however exactly in mind what I would want to build and what functionality I'd want. So I'll attempt to do that and see what comes out of it.
I'd personally be ok with keeping the logic in an eventsheet entirely BUT only if there's a good interface between the two.
If there's one thing I can pick I'd want, it's anything that avoids having to glue flowcharts together at runtime. It's probably useful in some cases, but I'd want to avoid it as much as possible.
If I look at a node, I have no idea if I glue a flowchart to it at some point or not. I can probably guess that I do, but I still have to check through the events to see which one. I'd rather have that connection already established in the flowchart view and be able to enable/disable this connection at will (checkbox in the flowchart view maybe?). It would be immediate visual feedback as to what's happening, rather than it being obscured in the eventsheets.
In the same vein, branching connections would be important. If I think a coinflip, I really want to avoid having to do the 50:50, then glue the correct following node/flowchart to the out. I'd rather have this already visually connected and somehow communicate which path I want to take. Maybe something similar to function "set return value" there could be a "set branching value" which is than simply compared against when "go to next node" is called.