torque on the foundation is clearly an engineering problem that will have a straightforward solution
as Oystia has indicated the materials cost of the propeller vs the 'water blades" is cheaper..
the engineering solution always has associated costs and efficiencies
higher toppling torque will cause higher foundation/support costs
modern wind turbines have settled on the 3 blade propeller...with aerodynamic lift..
although the old wooden windmills in europe were OK for grinding flour
they would not scale up economically to the height / power of modern propeller windmills.
no matter how good the engineers were..
as W has stated , there may be a unique niche market for the Aesop turbine.