The logical hole in this model is that the only distance scale used is based on the speed of light. More lightyears, as it expands.
The premise of spacetime is based on Special Relativity, the main axiom of which is the speed of light remains constant. If intergalactic light is being redshifted, it isn't constant to intergalactic space. If it were, the speed would have to increase, as space expands, but that would negate the explanation for redshift.
The idea seems to be that as space expands, these wavy lines of light are stretched, making them less wavy, but that's how we model lightwaves, not how they function. As with waves in water, they are caused by the energy moving through the medium and that energy is the light traveling. This goes to the issue of aether, but the fact is the only way the wave is observed is when it is absorbed by the measuring device. We can't actually "observe" light otherwise.
The reason why it is said to be an expansion of space and not simply an expansion in space, is because the rate of redshift increases proportional to distance, making us appear to be at the center of the universe.
Though we are at the center of our point of view, so an optical effect would seem to be a reasonable consideration.
While single spectrum light only redshifts due to recession, multispectrum light "packets" do redshift over distance, as the higher frequencies dissipate faster. Though this would mean we are sampling a wave front, not observing individual photons and raises the question of whether quantization is fundamental to the light, or a function of absorbing and observing it. Getting back to the problem that we can only know what we measure and have to infer the rest.
If it is an optical effect compounding on itself, that would explain the curve in the rate, so no dark energy necessary.
The cosmic background radiation would be the light of ever further sources, shifted off the visible spectrum.
So, yes, there are still dissidents to the theory out there, whether the establishment acknowledges us or not.
