"The "Herbarium" does not simulate being outdoors in any way. This promise fell short. I will concede that when writing this, such a plan may have been in the works and was assumed to have been finished by the time book was published, and even perhaps that the Herbarium was a compromised, lesser version of what Gene wanted (and eventually got in TAS and TNG) but I do not accept that this was exactly what Steve and Gene were describing in the book."
Well, to simulate outdoors was one (of many) intentions and actually I'm glad we got the Herbarium as otherwise they probably would have gone on location, shoot outdoors and then pretend it's aboard the ship which nobody would have seriously
But despite all the budget restrictions they could have made more efforts to feature some exterior windows on the Enterprise.