Pretty much. If we look at it really, really simply - let's just say there are 2 broad methods of creating attacks from the midfield.
Method 1) is to have a central figure responsible for the majority of creating attacking play. A very simplistic example would be Sneijder from our treble season. (yes, I know Maicon, Eto'o, Motta etc helped him out a lot but just bear with the example)
Method 2) is to have the creative responsibility shared between the midfielders. A team like Napoli is closer to this example. Players like Hamsik, Zielinski, Allan and Jorginho are capable of delivering a key pass and linking up effectively with their forward trio.
Now look at us for a moment. We CLEARLY lack a player to go with Method 1. Brozovic, as I've been saying for ages, is a great complimentary player in midfield. That's why he's very good for Croatia, playing alongside and balancing more creative midfielders like Modric and Rakitic. But he lacks the quality to be the tip of the spear for us in a permanent and reliable capacity. Joao Mario - while possessing different characteristics as an individual player, is more or less in the same category. i.e. (depending on the day,) a mediocre-to-strong complimentary player in a midfield unit.
Our midfield also seems to lack the quality to perform Method 2 to any high level. To stick with the Napoli example: instead of Hamsik, we have a second-rate Hamsik in Brozovic. Instead of Jorginho, we have a second rate Jorginho in Gagliardini. And instead of Allan, we have a second-rate Allan in Vecino. This is why we can't do a great job of method 2 either. Don't get me wrong, I'm sure if Napoli bought Vecino and replaced Allan with him, that he'd be better than he is here. But that's the entire point. It's hard for any individual (unless of obscene quality) or any unit to perform when everyone in that unit is more or less on the same level of mediocre-to-decent-to-strong (on a good day). Instead of a midfield of our "Hamsik", "Jorginho" and "Allan", we've ended up with a midfield of three Allan's. Three B-grade Allan's.. Do you see my point?
This is why I was so against the Vecino signing. Because we've added another decent-to-strong complimentary player, without addressing our lack of quality for both Methods 1 & 2. We've stacked the midfield with midfielders of the same level of quality. We've all talked about this before, think about the fullback situation with Santon, Nagatomo, Ansaldi and D'Ambrosio. All entirely interchangeable and all entirely 'decent' at best..
I do think Spalletti is going for a dynamic and athletic version of method 2 - similar to what he had at Roma with Naingollan, Strootman and De Rossi. But just look at those names and compare them to ours. It's clear that we lack the collective quality for the midfield to collectively contribute to the attack. That's probably the reason our entire midfield has contributed.. what, maybe 5 goals between the 6 players this season?