You have to remember, tanks back then were primarily designed to cross no mans land & enemy trenches. As such, had they been able to work out the technical difficulties. those huge wheels could have worked.
Although to me it looks a bit underwheeled in the back, I don't think it would have turned well by just the rear wheel. However, If they had decent brakes & throttles on those outboard engines in therory it could have had a zero turning radius. IE 1 wheel forward, one braking or in reverse.
If you'd mounted a pair of cannon, one on each side just underneath where the man is standing.. Each would have a good field of fire to the sides. Judging by the photo there was a fair distance between the wheels. Should have been at least somewhat stable. Top it off with a big gun or 2 pointing forward and it had potential to be a lethal weapon.
Biggest weakness as I see it, is that the wheels would not have stood up to arttillery fire. One good round of HE on the axle hub shattering spokes and its done moving.