An interesting view, but let's deal in facts rather than opinions...
What is the purpose of a modelling lamp anyway?
It's to give an
indication of what affect the flash will have when it fires, i.e. it will show where the highlights and shadows appear, and an
indication of their intensity. It's just an indication because unless the shoot is taking place in total darkness, there will be other ambient light present as well, reducing the contrast of the modelling lights, so the modelling lights won't show the true contrast of the image.
So for some reason those manufacturers who have fitted a powerful modelling lamp, which gives a much more accurate indication, are wrong? Would it be better to fit the useless low powered modelling lamps fitted to cheapjack flash heads? Of course not!
What use are proportional modelling lamps anyway?
Well, some people like them and there's nothing wrong with that, but the question has to be, "What are they proportional to?" and the answer is that they are proportional to the power output of that particular flash head, and to that particular flash head only.
Now, I'm not knocking other makes, just giving an example. I have various Elinchrom flash heads and generator units in my studio and every one of them has 300w modelling bulbs - that's a 333j, a 1200j, a 2400j and a 6000j, all using exactly the same modelling bulb - so if I was thick enough to believe that the brightness of the modelling bulb in some way indicated the power of the flash I would be in for a nasty shock!
The fact of the matter is that just a few years ago modelling lamps were not proportional, and photographers didn't let it bother them. They just used the modelling lamp to set up the shot and if, in an extreme case like this when there is a very bright modelling bulb shining on a very close subject, they just turned them off before taking the shot. At portrait distances and the like, the brightness of the modelling bulb would have no measurable affect of the colour balance. Basically, proportional modelling lamps were probably introduced as nothing more than a marketing benefit, rather than an actual benefit. The cost of including a potentiometer to turn down the light is, after all, negligable - but it looks good
Saying that a product is unfit for purpose just because a photographer needs to turn off a modelling lamp very occasionally is ridiculous.