Trying to understand your point about a blind alley. Do you mean a ramp-launchable boat that is a PITA to ramp launch? My perspective is I haven't met one that isn't a PITA to ramp launch.
errr uh, yeah... I don't know what boats you've had experience with, but we can probably agree that some are better than others. Ryley's Elliott 770 is not bad at all for what you get; although it suffers somewhat from much of it being assembled from lower-grade off-the-shelf parts such as the mast step he mentioned.
Aside from my I-14. That was easy!
Funny you should say; my limited experience with I14s is that they don't even need to be ramp launched, they are so light you can cartop the hull easier than a Laser. Standing the mast up is easy but all the rigging needed is definitely a PITA to my perspective.
This gets to a point often overlooked... how much stuff do you need to do to go from trailer to sailing or vice-versa? I've watched E-scow guys literally take 2x time than J-24 guys, because they want to have 50-leven things all strung thru the deck to multiple purchases & split controls; totally disconnect the rig & re-tune it every time, etc etc. They then will tell you how easy it is, without batting an eye.
A boat like Jim's GP26, which was designed as a no-compromise, fixed keel, high performance Cat 3 race boat, is likely going to be slightly more difficult to trailer launch than a purpose-built, trailer-launch sport boat of similar size.
How easy or difficult a boat is to launch;usually comes down more to how difficult it is to get the rig up, as well as how well your trailer is setup. That goes for fixed keel boats as well. Whether it ramp launches or not, if there is a good system for installing the mast quickly, it will be easy to regatta.
You are right though, we are a long way from the 7.9, thank god.
The 7.9 isn't a bad boat at all; I prefer it to the J24 by a huge margin. I was a member of a club with a few in the parking lot, they are not all that practical to dry-sail off a trailer much less rig/unrig for road trips. It's because the trailer-ability was totally an afterthough, so much of the stuff is in it's own way for trailering.
After some thought & searching I bought a Santana 23 which is very nice for dry-sailing off a trailer. However getting the mast up & down is a half-day 3 man job, just because (as before) so much of the rig is in it's own way. And it's nowhere near a sportboat in sailing characteristics!
As you say, much depends on how the trailer is set up. However care & attention to the rig is also well worth while.
As Jim said above, it's not going to be a trailer-sailer although I (and looks like many others) would dry-sail it off a trailer. And the performance shouldn't be compromised (or at least, should be compromised only a tiny undetectable amount). Since the rule was written with road transport in mind already, why not take the next step with it?