No, I don't think it is sensible to upgrade soon-ish. You say this is the best laptop ever that does everything you ask. That isn't going to change overnight and anything significantly better available tomorrow will also be significantly more expensive.
Someday 8GB RAM will become a problem, a new killer feature will require newer hardware, or Apple will arbitrarily end support over wifi drivers. However if it works great today then someday is probably at least 3+ years away.
Someday 8GB RAM will become a problem, a new killer feature will require newer hardware, or Apple will arbitrarily end support over wifi drivers. However if it works great today then someday is probably at least 3+ years away.