Yeah, the plan is to keep it sweet and simple. This was a one-off engine for Fix Your Mother's Printer and then we decided it was useful enough to release for other people to use.
I'm not against revisiting it occasionally to make smaller changes (what did you have in mind?) but it could easily turn into a project that eats up an unbounded amount of time and I'm definitely not looking to compete with Ren'Py or anything.
I'm in the middle of another project just at the moment but I'll see if I can find time to update it for Inky 0.15.0 sometime this week; thanks for the heads up!