Not long ago I explored existing weak-copyleft licenses. Surprisingly, there are essentially two of them: the LGPL, and the MPL.
I couldn't use the MPL because it had strange clauses about resolving legal disputes in California, which really didn't make sense in the context of my own project.
The LGPL and MPL are fine licenses but they both are a bit more complicated than they have to. I went with LGPL v3 but even it has strange clauses about static linking (in section 4) which would be a problem if my project were a binary library (fortunately it's a pure template library).
My prediction: the absence of a minimalist weak-copyleft license leaves a huge gap to fill. Any license filling this gap first will meet great success. Indeed, weak copyleft is quite consensual as everyone hates proprietary forks of FOSS project.