Have we been watching the same show? The first signs of a bit more than friendship were set in late season 2, in all of s3 it was a major storyline, it's what led to the cliffhanger at the end of the season, in s4 it was still about them (although there was only obstacles in their way), and their relationship finally concluded in season 5 when Cordy died, but not without that one last kiss we'd all been hoping for.
Is that what counts as brief these days? They might not have gotten all the make out scenes, but emotionally, it lasted at least as long as Spuffy.
For me, Cangel has always been THE main ship.
And I do think it deserves a spot as the main ships. If you think about, it does make sense. Buffy and Angel were the 'original' couple of the show. It already started in s1, and it went forth and back for literally years. I'm not a Bangel, but even I have to admit the tension this still created even in the later seasons. Somebody always brings up Buffy?Angel at some point during the season, implying that both Buffy and Angel are still thinking about it. And then there's the new school couples. Things heat up between Buffy and Spike, so they become the main competition for Bangel, as now there's people thinking screw Angel, Spike is better with Buffy. And just as there's somebody major new for Buffy, there's also a major new love interest for Angel (sort of mirroring the Buffy/Spike thing), and that love interst is Cordy. So, to me, as much as Cangel is to Bangel as Spuffy is to Bangel, therefore making it a main ship, one of The Big 3. The reason why I call it that way is because, even though all the characters on Buffy and Angel are in teresting, Buffy and Angel are and will always be the main characters, and being so sorta pushes their love interests furthest up front.
I'm a Cangel through and through 😉