Most traditional watch brands are very traditional and very classic. The less traditional ones are SUPER modern. Like MB&F and URWERK, they make things that look like they came from the future where space travel exists.
Piaget models are become so thin that they're using the caseback as the baseplate of the movement. They're becoming incredibly thin. Even Piaget's movements are increasing in diameter though.
I was worried about the Bulgari Octo Finissimo which has won so many awards recently that it'd be uncomfortable and feel like a dinner plate on the wrist. I recall the JLC Reverso Squadra XL felt very uncomfortable because it was a big thick watch with a completely flat caseback. Not comfortable at all that flat back! The Octo Finissimo also has a flat back, although it's not very thick and much less in weight. So far, the individuals on the forum here who own Octo Finissimo timepieces tell me that the watch is delightfully thin and lightweight since the bracelet is made in titanium that the watch feels very comfortable and that you "forget" you're wearing a watch sometimes. I wouldn't call it a "gentleman's watch" since I don't consider the Nautilus nor the Royal Oak gentleman's watches (and I consider the Octo Finissimo a part of that Royal Oak/Nautilus vein with its 70s design, Gerald Genta design, and the integrated bracelet design).
But my definition of a gentleman's watch may change in the next decade or so; I may change the definition myself, or popular culture may supersede my definitions if all the major brands start making large formal watches (hard to imagine right now, but who knows, maybe one day Piaget's best selling model is a 42 mm Altiplano Tuxedo. The future is definitely a big unknown!