I also would like to have a universal messaging client but sadly it doesn't seem possible , just look at the recent reverse engineerediMessage apps, why would you waste all that effort reverse-engineering proprietary chat apps, when they can get (and will get) shut down by the service. Especially while better, open protocols exist.
Sms isn't secure or private, it doesn't make sense to include it in a privacy focused messaging app.
I also would like to have a universal messaging client but sadly it doesn't seem possible , just look at the recent reverse engineered iMessage apps, why would you waste all that effort reverse-engineering proprietary chat apps, when they can get (and will get) shut down by the service. Especially while better, open protocols exist.