Any plan to support this 4 year old request?
This https://redmine.pfsense.org/issues/1388 was requested 4 years ago. Openwrt supports it using mwan3 and most off the shelf routers support it.
Any plans of incorporating this in pfsense?
It's been supported and used for years minus the auto-disconnect. It'll fail back over when the other connection comes up, but nothing will bring down the PPP session. Generally there isn't a need to bring it down.
The feature request is specifically for 'auto-disconnect'. There are a lot of providers which charge based on the connection time. So there is a need to bring up and down the ppp session.
And ignoring this request is a deal breaker for some of us.