Let me go back to Darwinian selection. My intention would be to defend Darwinian selection while rejecting the force model of natural selection. Well, I can't do that, but here is a sketch of an argument that looks promising to me:

1. In population genetics terms, Darwinian selection can be seen as a special, "boring" case of natural selection.
2. Darwinian selection is about the origin of adaptations.
3. There are models, other than usual population genetics models, for the study of adaptations.
4. The force view of natural selection does not account for the intricacies of these models of adaptation.
5. Darwinian selection can still be valued as a first step in the study of the relations (less obvious than often expected) between adaptation and natural selection.

1. The Darwinian, or "vernacular" view of natural selection can be translated into a (sort-of) elementary model of population biology. The only parameters in such model would be the reproductive rates of two variants. The model would constrain the population to be fixed in size, or limited in growth, and assume non-blending inheritance and asexual reproduction. It would be a rather boring model, with a predictable behavior for any choice of parameter values, but a legitimate model of natural selection. This is an indication that Darwinian selection can be construed as a special case of natural selection.

What I find interesting in the poverty of this model is that it is not just a poor representation of the world, but a poor representation of the (Darwinian) theory as well. The model is pretty useless as a tool to study evolution, but it also fails to capture many essential parts of the Darwinian view, including the asserted relation between function (new or improved) and fitness. (I use "function" loosely, as the effect of a part on the survival and reproduction of an organism in a certain environment.) 

2. As Coyne says, a better title for Darwin's treatise would have been "The Origin of Adaptations". One may also say that in devising a theory about the origin of adaptations Darwin provided the first insight into the fundamental concept of fitness, although his concept of fitness ("vernacular fitness") was fairly rudimentary.

3. As far as I can tell, the relation between function and fitness is not captured by population genetic models. There are good reasons for that: function would be, at best, an accessory to fitness, and it would introduce many complications since it is often difficult to define and measure. But even though we can study natural selection using models that do not represent function, it doesn't follow that the theory at large can dispense with function.

According to Orr 2005, modeling efforts in the study of adaptation follow the lines of either Fisher's geometric model, adaptive landscapes, or (perhaps more promisingly) mutational landscapes. I say "more promising" from the point of view of its integration with population genetic models. As I understand it, in Gillespie's mutational landscape model the effect of a mutation alter the contours of the adaptive landscape, thus changing the path (and probabilities) towards a fixed optimum. 

4. The force model sees the integration of variation and selection in terms of composition of forces (I'm ignoring drift and other population genetic processes since they are at least homogeneous with natural selection in modeling terms). Given the limited degree of integration in the models of adaptation and population genetics, however, the model of vector addition is arbitrary so say the least. In order to accommodate the mutational landscape model, the force view should include a dampening mechanism to the effect that the current application of a force reduces the effects of the future applications of another force.

5. The vernacular view is the idea that natural selection "selects" variable traits according to their differences in function. But the whole vernacular story does not discount the role of variation. We can have a vernacular view where variation "causes" natural selection to occur by providing it with the raw material on which selection "acts". Though philosophically objectionable, such view does not preclude seeing variation, and population genetic processes such as natural selection, as requiring different models, with the study of adaptations as the proper place to attempt an integration. The vernacular view could then be maintained as a first approximation to the scientific view(s), but not rejected as necessarily leading to false or inappropriate models.