The feedback I've received is that users liked the convenience of Tapatalk and don't like using a browser to access my forum on a mobile phone. So the shortcut idea is a good one, but it's still using the browsers. Personally I access my forum with my iPhone and Safari and have no problem with it, but others don't like it. Tapatalk spoiled them, and I had nothing but difficulties getting support from Tapatalk when I needed it, and really don't want to go that route again.
Many of my members commend me on how good my Xenforo looks on mobile.
I to want to stay away from FB groups
The trick is to let younger members (say under 40's) know what a forum (community) is
And some of the advantages compared to FB groups or Blogs
Eg more structured