If you want the efficiency of FT8 and the free form of a QSO, JS8 (JSCALL, whatever the name now is) is the way to go.
Force-fitting WSJT-X to be a free format QSO machine really isn't going to work -- hams don't expect it and don't really respond that way. You can do it, but good luck trying to find people to talk to.
I personally would go with PSK31 in such a situation except (as AA6YQ has noted) the prevalence of macros (aka "brag tapes") have pretty well destroyed its utility in that mode. Still, you can scratch that itch with PSK31.
The rise of FT8 has proved that hams aren't much for conversation and never were. And, why should we be? How much do most of us have to say to total strangers? It thins out pretty fast after the weather and the rig, doubly so if you're an actual DXer and are "talking" to someone whose native language isn't English.
Before FT8, Clublog's data showed that we had 8 to 1 as many QSOs on the weekend as the weekdays. Conversation was never our strong suit.
I've known lots of hams who spend enormous time on a very good station -- and do nothing but make 599 TU QSOs every contest weekend. The wonder station sit idle the rest of the time.
FT8 is winning because it is designed for us where we really live. What we most of us really care about is some sort of radio analogy of a catch-and-release fishing contest.
FT8 is spectrally efficient.
It positively discourages actual conversation.
It maximizes the ability to gain award-worthy QSOs.
It creates a wonderful "water hole" effect where everyone camps out. Most of the time (e.g. when Bouvet isn't on), that's a powerful and good thing.
Of course it's a big hit. Don't work it if you don't like it. But opposing it is the very definition of spitting into the wind.