Interesting thread.....I think 1/16 is suited to UH's range of vintage models, as I would say the majority of this market are people whom used to use these types of vehicles and now like nothing more than to view the large scale model version and reflect on it. I also think that this sort of collector is used to 1/16 being the collecting scale and 1/32 being the toy scale, which has been the case untill UH started producing the excellent 1/32 collectors models. If these vintage models were in 1/32, I feel they would be slightly put off by it, in terms of the loss in visual aesthetics, in other words, you would have to look a lot harder to appreciate the detail on a 1/32 ferguson than you would on a 1/16 model.
For more modern collectors, I dont think this applies and you could argue that UH could get best of both worlds if they produced in 1/32. Why they decided on 1/43, I do not know!
I think it is level playing field when comparing some 1/32 models to 1/16 vintage models, for example, the Tecnoma sprayer has immense detail and personally I think this is UH's most detailled model yet in all their scales.