Is it Coincidence that the Gospel of John is Called 'the Spiritual Gospel'?

This is what Clement of Alexandria - the ultimate 'Platonist Christian' - tells us about the Gospel of John, the fourth gospel in the canon.  But was it placed 'fourth' in the arrangement of texts because it was designed to be this 'spiritual gospel'?  In other words, did the pre-existent Christian interest in the Tetrad determine not only the 'desirability' of having 'four gospels' but also arranging the first three to be more or less 'identical' in basic structure and then the 'fourth' - i.e. the gospel of John - as something different because it was the 'fourth' - i.e. that it was related to the veneration of the holy tetrad?

It is worth noting that Philo already sees the creation of the heavenly beings on the fourth day as related to the holiness of the tetrad. In his explanation of this part of Genesis, in particular the fourth day of creation, Philo explicitly lays bear the importance of the number four within the context of the Hellenic philosophical tradition, a tradition marked quite clearly:

But the heaven was afterwards duly decked in a perfect number, namely four. This number it would be no error to call the base and source of ten, the complete number; for what ten is actually, this, as is evident, ten is potentially; that is to say that, if the numbers from one to four be added together, they will produce ten, and this is the limit set to the otherwise unlimited succession of numbers; round this as a turning-point they wheel and retrace their steps. 

Philo describes the underlying perfection, or completeness, inherent in the number four.  The tetrad was a Pythagorean numerical understanding related to the number four (1 + 2 + 3 + 4 = 10).  In Aristotelian terms the number four potentiality ten.

Philo also describes the sense of motion, or cyclical nature implied by this number four, which actuates to the number ten, as a “turning point” and “wheel”, alluding to the base ten that was used by the Greeks for counting and within which after the number ten one begins to “count again”, starting with eleven, twelve and so on. Philo also describes the number four as embedding within it three dimensional space, making it the perfect day (symbolically speaking of course) within which God should establish the foundations of the heavens within which the world of man was thought to be governed in antiquity, and speaking to the importance the field of geometry held to the ancients, a tradition that became the hallmark of the West.

Philo writes:

There is also another property of the number four very marvelous to state and to contemplate with the mind. For this number was the first to show the nature of the solid, the numbers before it referring to things without actual substance. For under the head of one what is called in geometry a point falls, under that of two a line. For if one extend itself, two is formed, and if a point extend itself, a line is formed: and a line is length without breadth; if breadth be added, there results a surface, which comes under the category of three: to bring it to a solid surface needs one thing, depth, and the addition of this to three produces four. The result of all this is that this number is a thing of vast importance. It was this number that has led us out of the realm of incorporeal existence patent only to the intellect, and has introduced us to the conception of a body of three dimensions, which by its nature first comes within the range of our senses. 

And lastly, in reference to the four elements, and four seasons upon which the ground and order of human existence ultimately rests, Philo concludes with the following summation:

There are several other powers of which four has the command, which we shall have to point out in fuller detail in the special treatise devoted to it. Suffice it to add just this, that four was made the starting-point of the creation of heaven and the world; for the four elements, out of which this universe was fashioned, issued, as it were from a fountain, from the numeral four; and, beside this, so also did the four seasons of the year, which are responsible for the coming into being of animals and plants, the year having a fourfold division into winter and spring and summer and autumn. 

The point of course is that it is unmistakable that the Gospel of John, the fourth gospel, is very different from the three that proceed it in the canon.  The other three have the same basic order and verbatim linguistic features shared in common.  John stands almost completely outside the other three.  Could it be that it was designed that way?  Could it be that as the fourth gospel it was designed with a specific 'spiritual' purpose in mind?