The fictional plants just need a little love, IMHO.
The above quote is mostly about the "McNugget" like feel they have, which is mostly caused by their not having been refined and purified as ideas.
Natural plants have this refinement built in-- Things like the mythological silliness behind mandrake roots, et al.
Toady is busy bashing his brains in on logic problems, loop execution optimisations, bug hunting, etc. All too often, this precludes taking time to sit and daydream about fantastical components of his game.
I suspect that it is this time constraint issue in regard to spending the time to refine the fantastical elements into beautifully complex abstractions on which "cultural" things can hang that is the real motivator for him to scrap them.
Personally, I think things like plump helmets, sunberries, and such already HAVE cultural significance--- They have significance here in our forum community. We have each tried to envision these plants as best we could from the limited information available, and a wealth of community stories have been crafted, (of various levels of quality, which I wont elaborate on) which when taken together, could be used to flesh out these crops, if one were to take the time to do so.
At the end of the day though, it is toady at the wheel. If toady decides to axe sunberries and pals, I fully expect the mod community to do the fleshing, just because of this community cultural growth those crops have produced.
There aren't that many of these "original plants", after all. The new raw structure has been (mostly) finalized for herbaceous plants. Some real-world biome evaluation for plant morphology and some inventiveness, and we can have a new-raws compliant "original plants" mod. Probably a great many to pick from.
Who knows, if the community distilled versions are of good enough quality, toady might decide to incorporate them. Again, I think the real issue is the time and energy needed for that distillation and refinement.