Yes, the gunbarrel certainly sets a mood but I think looking at something like Skyfall disproves that. Similarly, I imagine if a faithful, period-set Fleming adaptation series was made, it would feel as authentic and "canon" as the likes of FRWL, OHMSS, FYEO, TLD or GE without the need of tropes like the gunbarrel.
So if legalities weren't an issue, I'd no longer have qualms about a Dalton or Brosnan starring, "unofficial" Bond film bringing them back one last time. The November Man, with a few tweaks, could certainly be Brosnan's 5th Bond film, for example.