Control over the opening and closing of the pallet is minimal. It *can* be noticeable but often isn't. When there is wind pressure involved, as soon as the seal is broken, the pressure neutralizes (and quickly). Now, on a real pipe organ you can get different speech characteristics assuming you are highly highly trained and it is a good instrument with good touch. You can "choke" a pipe's speech for instance. But the truth is, in most normal playing, the effect is minimal. You have to often be very deliberate and extreme to articulate such effects. The closing of the pallet is perhaps more easily controlled due to the mechanics of it (providing resistance in stead of breaking a seal). But in a hauptwerk setup, these things are almost completely irrelevant. Then it falls down to simple preference.
On the one hand, I often frustratedly think that the tracker/pneumatic touch debate is completely fruitless. I've played many instruments, many that are not trackers that feel
very nice because they have high quality keyboards with well-regulated contacts. But then I stop myself and think of other types of instruments as well. Trackers have a true feel. They are the sum of their parts and are much more than a simple fulcrum like electric organs are. As organists we are sensitive to that. Some like it, some don't. Much the same way, pianos have a feel. There is the feel of upright vs grand (and expensive and cheap for that matter...) And the good Lord knows that digital pianos are all over the place. We certainly wouldn't begrudge a pianist who was buying a digital piano for trying to find a keyboard with the most authentic grand piano-like action they could find, and much the same way, organ transmission was the same for hundreds of years before electricity came along... that feeling is a legitimate choice and something worth emulating for many. OTOH, there are musicians who like "synth-action" keyboards. I don't get it personally, but they exist.
There are often times people become sensitive to something and don't even know how to properly articulate that fact. THEY KNOW it when they FEEL it. Just can't put a finger on it......so to speak
I suspect it is the same for people who have an affinity for tracker touch keyboards.