They seem to be missing the point of tanks.

First, tanks are fast. An M1 can hit highway speeds on the highway. They actually have to put a speed limiter in them during peacetime, because a 68-ton vehicle hitting 65MPH will do a lot of damage to the road. This? I'd be surprised if I couldn't outrun it on foot.

Second, tanks can go on all kinds of terrain thanks to their low ground pressure. Those treads aren't just for show - they spread that weight very effectively. It can exert a ground pressure as low as 15psi, while wheeled vehicles are usually in the 30-40psi range. This thing's going to weigh as much as a tank, but channel all that weight into a few small legs. Put that thing in the mud, or sand, or snow, and it's going to be useless.

Third, tanks are low to the ground for their own protection. One of the essential tactics is defilade - using terrain to hide your hull, but leaving the turret exposed. It's like infantry taking cover behind a wall - you can shoot, but you're protected from being shot at. The higher your hull is off the ground, the harder it is to find a good hull-down position.

Now, I will grant them that a high-legged design like this would be effective protection from IEDs. But tanks are already damn near impervious to IEDs - it took almost a ton of explosives to take out an M1 in Iraq, in one of the few times they succeeded in taking one out. Usually all an IED manages to do is a mobility-kill - break the treads, so it can't move, but all weapons and armor still effective. So IED protection is not really a big advantage anyways.