I have all of one such knife in my collection, so I am no expert. But I tend to agree that something slim, compact with first rate materials and elegant lines is what best fits the bill. One hand opening is an absolute non-issue for me. I don't find using two hands to open my knife to be a particular cumbersome chore. No ss for me either (although it wouldn't be a deal-killer).
Mine has a forged 52100 blade, fossil walrus ivory scales and elegant English scroll engraving with gold highlights. Very gentlemanly, IMHO.
The pictures don't show how very thin this knife is - it slips into the pen sleeve of my suit pocket and disappears. Very discreet.
Knife by Bailey Bradshaw.
Roger