Thanks for specifically addressing your in-game experience with Zweilander combat.Second session was earlier today. There were two combats, or more accurately, one and an ambush.
Combat, in my opinion, was nice. Flowed smoothly. It went a bit slowly because we are still feeling our way around the system. And this dovetails directly into your point about Weapon Qualities.
There are 24 Weapon Qualities. Each confers some variation on the weapon's effects. Some are relatively minor, some are more consequential. So, when you have a weapon, you need to be familiar with its Qualities (and many weapons have two or three) and what they mean, as does the GM. Zweihander's balance really comes into play here, and when a Weapon has an advantage in one area, it will usually have a disadvantage in another. Understanding how these Qualities work, not only separately, but in combination, is key to "getting" Zweihander's Combat system. This, coupled with the Action Point system, leads to a style of play that encourages a certain tactical depth without being overly complicated. For me, it's just about right. There is a bit of a learning curve, as my group and I are still internalizing the Qualities, but my group likes it, and so do I. And this is a group coming from Labyrinth Lord. YMMV, as always.
I would agree that it's doesn't seem very "flashy" or "swingy" on its surface, but it worked at our table. The Qualities did give each weapon a different "feel" and in-game utility.
In short, I liked it, it seemed to flow very well, and I think it'll get much faster as we stop having to look up what the various Qualities do.
It sounds like it would be something I like, just in terms of keeping crunch and flash at a manageable level.