Work is certainly a useful tool for introducing the kinetic energy. The idea of starting with a single steady force acting on a point mass producing simply and directly the quantity 1/2 m v^2 seems to me to be a quick and easy way of justifying giving the most basic energy (kinetic) that particular form. I feel much more comfortable with that simple justification than simply pulling 1/2 m v^2 out of a hat and defining it as KE. One can then develop the simple potential energy of a point particle in a gravitational field, then simple energy conservation of a projectile, and then drop the whole idea of work completely. Then a recursive definition of other energies, as John has proposed, takes us wherever we need to go to include all the energies required to keep conservation valid.
Simply starting with energy consevation out of the blue and ignoring its link to Newton's 2nd through KE seems too authoritarian - even though it's a valid approach to physics.