(TL;DR people can scroll to the bottom)
Though I enjoy football ardently, I'm not particularly fond of its mangas as they tend to be overly unrealistic and unoriginal. Having said that, I still gambled at reading Ao Ashi, hoping it wouldn't disappoint me like some others; and to now, I'm actually pretty happy that I did so.
Now, Ao Ashi's story is to a certain extent unoriginal. You have your main character- Ashito- a middle school kid with an insatiable thirst for scoring goals and of course, he wants to go pro. After fierce competition he finally gets handpicked by scout Fukada-former Japanese star now retired due to injuries. From then, he tries to climb the ranks of FC Tokyo Esperion's youth academy. Sounds familiar? I'm sure that this young-kid-wants-to-go-pro motif is nothing new but I can assure you that, there are fresh elements in the manga. The fact that Ashito isn't precociously equipped with world class techniques and tries to offset these shortcomings with tactical acumen and hard work is realistic, and commendable (I'm looking at you Tsubasa). However, impatient people should know that the plot progresses slowly.
The mangaka has also done a great job to portray the events unfolding on the pitch. You can clearly see what is happening, the effect of precise crosses, the damage of accurate through passes,... and most of all, the positional and spatial awareness of the players themselves. The mangaka should be praised for his great work in drawing what would normally happen on a real pitch cleanly. Moreover, the character designs art-wise are also acknowledgeable. The attention to detail is absolutely excellent.
The story also possesses football stereotypes in terms of its characters, which makes it realistic and enjoyable. You have the dickhead defender who always try to murder the attacker, you have the technically gifted forward who can humiliate defenders with few touches, you also have the guy who is abysmal with his technique but have an acute brain that makes him shine. To put it simply, the characters are highly relatable and should make the experience pleasurable.
It is true that the pièce de résistance of Ao Ashi is its realism. There is a realistic aspect in most details of the story. That talent alone won't help you go pro is realistic. That technique alone won't help you win matches is realistic. That awareness at all times is key is realistic.
All in all, for ya lazy TL;DR folks, Ao Ashi is greatly realistic, relatable and enjoyable in many ways. For football fans who wants a break from unrealistic things and are patient with glacial plots like me, this is the holy grail.