I agree and disagree. I do think that the transfer fee has clouded people's judgment of Fabio--people are expecting him to be a 35 million pound player now instead of in the future. If he had come up through the academy, then many, many more would be clamoring for him to get more minutes.
No doubt that he improved this year, despite not scoring. I'm probably biased: because I believe that he has great potential, then I probably overcook what he does on the pitch from time to time. I will disagree with you (quibble?) that football intelligence can be learned while pace cannot. While coaching can definitely help a player with positioning and making better decisions, I also think that the great ones are much more instinctive in their movements--they just know where to slide into spaces or find those passes and layoffs. This is Fabio's great strength in my opinion. He plays like a much more mature player. On the other hand, speed and strength are largely inherited, genetic traits; however, one can get demonstrably faster and stronger with effort and work. Because Fabio is still a teenager, he has a lot of room to grow in this area as his frame fills out. To my eyes, he was quite a bit quicker and stronger this season than last.
In regards to the loan, I'm ambivalent. I can see how the Sheffield loan really helped MGW (mentally/confidence-wise more than anything) and the experience of being an everyday starter would be invaluable to Fabio. On the other hand, I really can see him breaking through next season, especially if we go to a 4-4-2 and he plays as the second striker. If we bring in a target man and a second striker/winger like Guedes (and keep MGW), then Fabio might just go out on a loan--but I would be very, very picky on where he went.
I like Fabio - he always has time for the fans and his teammates. He works his socks off, too. What else do you want in a young professional?