Gundogan is clearly the better passer for sure. Agree 100% - nonetheless, Fernandinho's passing is already fucking phenomenal.
It's our current lack of pace in our fullbacks that exposes us to the extent that our lone pivot must be extremely fast and excellent at winning the ball back.
Fernandinho seems to be faster than Gundogan by quite a bit; and Fernandinho is probably better at winning the ball back.
Vision - this is a curious thing. I think that from an attacking perspective, Gundogan can spot better passes than Fernandinho.
Vision on defense - where you must anticpate a counter - where you must see where the ball is going to be played next - Fernandinho is absolutely freakishly good at this. I haven't seen enough of Gundogan on defense to compare - but I doubt that he'd match Fernandinho in this department.
Play Gundogan as an 8 - he'll kill it there.
Play Fernandinho/Garcia as our lone pivot. They'll excel there.
And if we go with a dual pivot - slot in Gundogan as one of them for sure.
Gundogan is massively diverse - he's world class at the 8, or as part of a dual pivot, or as some sort of free-wheeling midfielder, expected to contribute on defense as well as offense.
Bottom line is that we need Gundogan in our starting lineup as soon as possible.
I know this is very simplistic but if you look at Gundogan's interception stats they suggest that he has good vision in defence.