I don't know if this idea is feasible...
In terms sound/dialogue, you might try and explore a "mumbler" (dialogue creator) of sorts. Some people find "reading dialogue without vocals" a bit disengaging. But, with a "mumble creation tab" your users won't have to find voice actors (which complicates things). They could just assign long or short "mumbling sounds" to each dialogue line.
The trick is to find a way to "stretch, speed up, raise and lower the pitch" for each character. I forgot to add a preview/play button to my dummy tab below... but I hope it gives you an idea of what I'm trying to say.
And OBVIOUSLY your users will be free NOT to use this mumbler, if they are happy with text-only games. 
Here are some samples of what the games would sound like: (I just think this would be a really fun and unique way to keep things simple... if it interests you, or if its a doable thing. I'm NOT a dev, so I would NOT know what it takes to make what I'm asking for.
