AFAIK no one has taken the time to sit down and compare new ticket with any of the 4x ticket trackers. One of the latter uses the 4x workflow package, which sounds like the right thing to do.
Your enhancements sound interesting, in particular the ticket history graphing and prioritization. Searching isn't quite as interesting to me in the 4.x context because the solution there is to tie into the upcoming Full Text Search mechanism which is looking very, very promising.
If you're interested in porting new ticket with your enhancements to 4.x, I think you'll find interest here, too. Here's a suggested sketch of the process, just off the top of my head, wearing my OpenACS 4.x project leader hat:
1. Do a feature comparison with the existing 4.x ticket trackers (Vinod may be able to help you here, as he's ported them)
2. If you find that they're so slick that we should shit-can new-ticket, let us know and tell us why. My guess is you won't, of course. More likely is that you may find a feature or two that would be good to have in new-ticket, and that we'll want to investigate adding them.
3. If you're interesting in porting, it would be very good to have ticket descriptions stored in the content repository (so we get Full Text Searching on them for free) and to have it use acs-workflow and acs-mail/acs-messaging or whatever the heck JonG says is the right thing to use for alerts. These changes would make the package consistent with the 4.x design (tickets themselves might want to be objects, in order to get permission handling from the 4.x permissions package).
4. If you're really ambitious offer to port the SDM to 4.x, too :)