I have previously, and rather extensively, studied a form of TCC that was nearly completely stripped of all outward expressions of Chin Na, so I guess my perspective is slightly different.
That particular branch holds the fingertips of one arm to the wrist of the other in most of their form movements, which almost precluded coming to an understanding of actual application from studying their form alone. You had to find a qualified teacher of that style just to give you any kind of idea even what a forms martial intent would be.
Since such teachers were few and far between, not many people got much more than the form in that style.
Try to figure out Chin Na from that type of movement sometime and then we'll talk about how much Chin Na YCF removed from his form.
As for it being too low...
The Yang family used to have their students practice their forms under a bread rolling table. They believed that was necessary in order to give their students legs the requisite strength for the application of TCC.
I don't know how much lower than that you can go.
I, for one, am greatful they don't require that anymore, as I'm quite certain I couldn't do it.
Things change. TCC is a developing, dynamic art. It seems to me that the longer the art goes on, the more Masters put their input into how it should be done, how it should be taught, what is taught, to better the art will get.
Because of that, I tend to lean toward thinking the modern forms from legitimate Masters of the art, such as Yang Zhen Duo, Yang Zhen Ji, Yang Zhen Guo, Yang Jun, will be at least as good, if not better, than anything you would have been taught long ago.
It's had longer to develop, be tested, tried, taught over and over again. There is now more data to go on as to what way is best to teach the art. It's been standardized somewhat since the time of Yang Lu Chan and Yang Ban Hou. I don't know that that is a bad thing. I actually tend to think of it as a good thing.
What doesn't work will be left behind in favor of what does work.
I truly do not undertand the concept of "just beause it's older, it must be better".
I don't think you're going to find any Master of a particular form that is going to agree that someone elses forms are "better" or more "martial".
How martial a form is will depend entirely on who is doing the fighting and how well they have learned their art, not on which form they have studied.
Learn the form you choose to practice to the best of your ability. That will be far more productive than trying to compare or contrast the different styles or the forms of different Masters over time.
If you are convinced your Master has the right stuff, then practice as he dictates without deviation and you do very well.
My real point is that most of the "differences" you will find in between the styles, and even in between the forms of different members of the same style or family, are mostly differrences of external manifestation, not internal principles.
As long as the internals are maintained and properly taught and practiced, the rest is simply window dressing and differences of opinions between various Masters of the art as how best to externally display those internal principles.
I don't know that comparing or contrasting different Masters forms will really tell you very much, except that different Masters have differences of opinions on things.
In my opinion, for what that's worth, it would be better to concentrate on whatever it is your chosen Master is teaching you. Unless you're writing a book about the differences in between different Masters forms, I don't know that the effort will really produce any meaningful results.
I spent a lot of time researching such things in the past. While it has always proved a delightful way to kill time, I can't help but feel in hindsight that my time would have been better served actually practicing my form rather than comparing and contrasting apples to oranges.
It was always clear to me that you were not disparaging Yang Cheng Fu. I hope I did not convey a different feeling. If I did, I apologize.