Returning to this topic, I'd like to present some opinions regarding this matter:
I gave a lot of thinking to the why in this regard, and at first, I was ready to allow that, put simply, the order of the zodiac represented an archetypical model, that then, we should use in order to access meaning for different locations. Simply put, we would get the original model (or "perfect chart", if you prefer) created from observation of the cosmos, and compare it to our localized charts in order to see how things develop. For example, if you cast an Aries ingress chart for the northernmost city you can think of, you see that it's likely the Sun will not aspect the AC (I did this a couple of times) and that is descriptive that the Sun's light will not have access to the AC for some time even in spring's beggining. That's why sometimes different climates strike near regions, cause through accidents they acquire different AC degrees in different signs and likely affinities. Just like a person, regions have different cycles and dates to be "born" that follows certain patterns. But that's not the only conclusion I came to...
Let's take a look at what causes seasons to happen. First, we have precession of the equinoxes. According to some researches, Hipparchus already had knowledge of this (150 B.C), so it's difficulty to allow that this concept was not integrated into tropical astrology, even with understanding of some of it's implications, if they really wanted/needed to. But as a matter of fact, it was to the best they could, in my humble opinion. I'll drop this for the moment and let's see the other movement that causes seasons, the secondary one (that also have fit symbolism):
According to Wikipedia:
Seasonal weather differences between hemispheres are further caused by the elliptical orbit of Earth. Earth reaches perihelion (the point in its orbit closest to the Sun) in January, and it reaches aphelion (farthest point from the Sun) in July. Even though the effect this has on Earth's seasons is minor, it does noticeably soften the northern hemisphere's winters and summers. In the southern hemisphere, the opposite effect is observed.
Now, imagine precession does not exist, and let's take the thema mundi and the classical order of the zodiac. According to the thema mundi, the world begun in Cancer. According to the classical order, Cancer is placed in the bottom of the zodiac, where Earth finds its aphelion.
Now, what is precession? Is it not derived from primary movement? And is it not, from a geocentric perspective, derived from an opposite movement to the secondary one? So, the problem here, is to reconcile one type of movement with the other.
Now, the summer quarter (from Cancer on) heats by essential significance in secondary movement (it begins from the coldest point and up) and by accidental cools down (as the Sun will find its highest position in the sky in Cancer and can only go down from there, now precession allowed). So follows autumn. But that's for the northern hemisphere. For the southern, the summer quarter still heats up by secondary essentially, but by accidental the Sun will also heat up, and then, spring follows for us. Let's jump to the winter quarter now: is it not true that by essential significance this quarter cools down, as the Earth reachs it's perihelion, and then it can only go downwards in terms of heat untill it can start heating again at aphelion? Maybe the joy of the Sun in 9th (close to its strongest point) and it's exaltation in the 19? of Aries (10th sign from Cancer) are related to these...
All in all, the differences felt in opposite hemispheres are related to how primary movement and consequently precession affects the positions of the angles in a chart (if there was no precession, there would be no seasons? I can surely tell that would not be the case, although the differences between them would be minimal). So, in relation to the ecliptic, it can not be shifted, simply because, it's correctly fixed in the equator, an area that is the least one subject to the accidents caused by mundane position.
As a side note, the creation of divisions should have come from this very problem (and that's also why division is a Tropical Astrology tool, since it would not be very usefull in a sidereal vedic enviroment. At the same time, it gives us more to work with, which is good!). The differences from one hemisphere to the other, or even from one latitude to another in the same hemisphere, are not so radical as to provoke a full inversion, what occurs is a variation (up to 23,5?) due to the earth's rotation that creates angles in a chart diverse to the ones natural to zodiacal signs (The Cancer and Capricorn tropics receive this name cause that's when the Sun achieves the zenith in their respective hemispheres, but they are not fixed in the zodiac at all). So, these strong seasonal qualities are more related to the primary movement than to the secondary one (although this secondary movement has relevance). Also, this may point how accidental signification can be really important, since it's strength affects seasonal cycles a whole lot more than the essential one... But, the framework against this "accidental quality" still retains its universal meaning! That's why we still get good results down south.
Also, the focus I put on precession does not mean I advocate precession correction for return charts, since that would kill the symbolism of the degree marked in secondary movement.
Ps: if I said anything absurd or incorrect from a technical perspective, I ask forgiveness. I'm not very well versed neither in math nor astronomy, and to grasp certain concepts take me hours sometimes. I'll gladly erase the post if any huge mistake have been made in my statements.