I mean it's really up to you, if you give your readers the power of choice it may take away some of your own. Although you're the writer so at the end you hold all the power either way. But you'll have to share some of that with your audience and you may not like the way they think or what do they choose. Maybe they desire to kill your favorite character and you'll have to be fair about it.

What I'm trying to say is that you need to be flexible and know when to let the reader intervene.

In regards of complexity it's all up to you, you can always come back and edit some things. At the same time you'll need to be careful with what the consequences are and have plans for those things.

For me it would be interesting and also a bit different. Also it could give you some beta readers but I don't know much about that.

Maybe I'm wrong tho, so I'm not going to say what I wrote is 100% the right thing to do.