While I certainly take your point, to be completely fair, Glen would have had a much tougher time pulling this off than Terence Young or Guy Hamilton had when they were making the early Connery films. At that point, there weren’t really any expectations for the films and Terence Young, and then Hamilton after him with Goldfinger, were establishing the template that future Bond films would end up having to follow to some degree. If you’re setting out to establish the template, so to speak, the chances of you landing on something iconic, even by sheer luck, is far higher than if you’re a director who is locked into certain aspects of a template that has already proven to work time and time again for the span of multiple decades.
While I certainly don’t disagree, and would probably give Terence Young the edge in a debate over who the best Bond director has been, Glen’s work ultimately, I believe, led, albeit somewhat indirectly, to some iconic work down the road. Had he not taken the gig when he did and helped EON reign in the series from the outlandish and comedic direction it was headed in, and pulled it right back to earth with For Your Eyes Only and then kept it on that track through the end of his tenure in 1989, I wonder what the franchise would look like now. His greatest contribution, I think, was in showing the world that the franchise could transition from Roger Moore into a more serious direction with Dalton. Without his work on The Living Daylights, which perfectly nailed that tone that distinguished itself from the Diamonds are Forever through A View to a Kill era while still maintaining the essence of Bond, the franchise might have continued to drift in a more comedic direction, as there is certainly room within the script of TLD for that to occur (since it’s been said that the script was written either with Moore or within a rather generic Bond in mind, rather than either Brosnan or Dalton specifically). This set the stage for Brosnan to come in and have his somewhat middle of the road take on the character, where it was a blend of Connery and Moore, rather than going to one extreme or the other, before giving way to Craig’s decidedly Dalton-esque approach. Without Glen’s work on The Living Daylights, I very seriously doubt that there is a Casino Royale down the road, at least not in the form that we ended up getting. Terence Young gets the nod for setting the template and a lot of the Bond iconography. Hamilton gets his props for Goldfinger, but I have a hard time ranking him too high on the list because that’s the only solid Bond film he made, while his other three efforts are substandard entries in the franchise. Glen had that consistency that Hamilton lacked and also helped pave the way for greater things down the road for the franchise, even if the audiences weren’t ready for them at the time that Glen was trying to do them himself.
And the franchise finds itself in a similar position now, albeit at the other extreme. They’ve spent so much time doing the personal stories, rehashing the trust issues and MI6 incompetence (and relevance) angles time and time again that it might take a director to come in with an idea to shake things up and talk EON into going in a direction that doesn’t involve us seeing the same things that we’ve seen from pretty much every film post-TLD. It’s funny that, for all of the complaining that people do about LTK, it’s one of the most pilfered films in the franchise. They’ve been going back to the well for ideas that LTK brought to the franchise first, with the personal vendettas, the revenge angle, Bond going rogue, etc., etc. that a new director might need to come in and talk EON into taking something more from something like The Spy Who Loved Me than anything else.