I'm a lefty too. Whatever the convex geometry on the right face of the Ultimatum does for right handed users, it doesn't hurt us.
Considering that the Ultimatum is not at all thin, a left-handed users might expect food to stick to the (fairly flat ground) right face, but that hasn't been a problem for me. Technique helps too: If you keep your knife straight up and down, keep it moving, and finish with a glide (or draw), that will minimize sticking as well.
The shape of the knife makes it a natural for people who use a gliding action
. I do, and that's one of the things I like most about it.
Like so many other things about the knife, the 245mm lengths is part of its versatility. If it were shorter, it wouldn't have enough flat; if it were longer it would turn into a heavy and awkward chef-de-chef. As it stands, it's the same usable length as any of the so-called 10" chef's knives in my motley collection of old and new Sabatiers.