Watermelon:
I agree that it is preferrable to design your own connections and include them in your sealed engineering drawings. We do that currently in all our projects.
In the U.S., though, common practice through the years has been to delegate this task (for common shear connections only) to the fabricator. The thinking was that you lose economies if you force fabricators to make connections that are not to their usual standards.
On one of our more famous collapses, the Hyatt Regency walkway collapse, the engineer did just that...delegate a connection design to a fabricator. The fabricator started the connection design, but then got busy on other projects and let the job out to another fabricator who saw the detail that had already been started and assumed it was complete. The connection was fabricated per the original fabricator's drawing and was built. The EOR failed in fully checking the connection but insisted that it was the fabricator's responsibility to correctly design the connection.
The judge ruled that the EOR could delegate engineering tasks to others, but the EOR could NOT delegate his responsibility for the entire structural integrity of every part, including the connections.
Today, we delegate all sorts of things for others to engineer. Steel Bar joists, metal deck, prefab wood roof trusses, etc. are all engineered by others. We trust the load tables and specify that they be designed per SJI, SDI, etc.
Standard, shear-type connections can be considered as no different from bar joists as long as you, the EOR, understand that you are still responsible for the connection's adequacy. I'm not sure its "sloppy", but I'd agree that I prefer doing them myself.