All in all, I hope for the best, but lets take a practical look at things, intelli's a generally busy person and when he's got time, really comes out with quality stuff. It's been a while since he last actively played so we can only hope he's nearing another time period where he has free time to dedicate to the server, whether that means v5, or just a minor change to v4.
I also really don't think its necessary to wait until 1.9 is released to introduce v5/ a new beginning since no features in 1.9 require a map reset in order to enjoy. Most of the changes are functional and the only changes to terrain are in the end, and that can be easily reset when we do see 1.9. We're about a month away from 5 years that this servers been up, and I just hope its not this much of a ghost town then.