Triple triangle is just a gimmick
It's next to impossible for the triple triangle not to have an effect on overall frame mechanics - the relationship between stiffness of top tube and down tube and rear end stiffness, and these things all alter "planing":
Performance: Our research has shown that the frame determines the performance of a bike. The frame must work with the rider, allowing them to generate more power with less fatigue. Such a frame will encourage the rider to go faster and ride more.
It appears that the stiffness of the frame, and especially the balance of the frame tubes, is crucial for creating a frame that feels “lively” and eager to go. Based on the preferences of our testers, Jeff Lyon used thinwall tubes in standard diameters for our L’Avecaise test bike. The result one of the fastest bikes we have ridden.
Interestingly, the best carbon frames use a similar balance of the frame tubes – relatively flexible top tube, somewhat stiffer down tube, very stiff chainstays. On the other hand, even small deviations from this formula, for example, an oversize top tube on an otherwise standard-diameter frame, do not seem to work well for many riders. Thinwall oversize tubing can offer great performance, as long as all tubes are increased in diameter, and the balance of the frame is preserved.
The triple triangle is going to change how that top tube behaves. The obvious thought is that it will stiffen it - because it acts as a brace it might actually allow thinner flexier tubing in the earlier part of the tube. It also effectively shortens the top tube for structural purposes without changing rider position - so it allows top tube length to be one thing for flex, and another for centre of balance.
So it's very hard to see how the design could NOT have an impact on handling - it would either have to make it better or worse; it can't be neutral. Given that the Zaskar is normally described as having exceptional climbing and acceleration, that GT was a very engineering focussed company before the founder's death (http://sidewaysandfallover.blogspot.co. ... ycles.html
) and the obvious purpose of the design is to improve these, it seems reasonable to believe that the triple triangle does exactly that.