Thanks, for my lab I did upgrade to 2.0, but there was no significant need for me to upgrade the old 1.7 stack which is working nicely already. The migration would mean redoing the labels and risk major downtime.
There's still a few glitches that need to be addressed in 2.x such as the api dashboard. Plus the forcing of people to go to the EE version if they want HA. I've done rolling updates using docker stack deploy of Traefik with the consul successfully so far at least there was no noticeable downtime (i.e. uptime robot didn't complain).
So there's no immediate drive to upgrade. Generally I would follow that rule where if there's no actual business value or development value don't bother.
As far as business value goes, because of the TLS forwarding, we can reduce our EIP and swarm count by merging two swarms and having it route "intranet" requests through an internal traefik. Though it costs less on paper (and I've implemented that on my lab) it is not really worth having the risk of mixing two vastly different concerns because the cost of the machines is cheaper than human cost.
Like I said, I just did it for my home lab, which is running off a cable modem so I only get one external IP. To prove it can be done.
Some tips I can share is to use the "chain" so you can reduce the work. that's what I did in Trajano base Docker swarm stacks