I don't think so. Being myself south american, I think I have met too many "Enzo Fernandez" types during my life. I think take him out of Argentina and put him straight in a country like England would be counter productive. Very demanding league, lots of competition, but most important, really different culture. Sometimes, it can be like a fish out of water.
So I think the best development for him would be exactly that - Go to Portugal, learn more about european football and Europe itself in a less strange environment, then move to England.
At the same time, I also think he's not the perfect type of player for Arsenal right now. Too much box-to-box. I think the perfect player is more of a regista, a tempo-controller.
I agree with most of that except the bit at the end. I see Enzo developing into a quality regista. Actually see a bit of Toni Kroos in him.
P.S. you should post more often.