My personal impression:
Since we don't have Neymar anymore, a burden is on Messi, but it is not THAT bad thing.
This is my estimation how we played with Neymar-Messi last year:
Our team gets, let's say, 50 actions per match.
Messi tries to do something in 20 actions.
Neymar tries to do something in 20 actions.
Other players try to do something in remaining 10 actions.
Now, Messi will create something (a shot for himself after a solo action, or a shot for Suarez/Neymar) in let's say 5 out of 20 actions.
Neymar will create something (a shot for himself, a shot for Messi/Suarez) in let's say 2 actions out of 20.
So, out of 40 Messi-Neymar actions, we would get 5 (Messi) + 2 (Neymar) actions after which something would happen.
The KEY THING is, Messi will create "something" (a shot or a key pass) way more often than Neymar.
Now, Neymar is gone, his solo actions and turnovers are gone and now Messi has to do all by himself.
But, that also means that he is involved way more than last year and he will try to create SOMETHING way more often than last year.
And again, since he is WAY better than Neymar in creating something (out of 20 actions), that means that Messi will have 40 actions in this season, and in the end, our team will create 10 chances out of those 40 actions, compared with 5+2 chances with Messi+Neymar.
So, if you get my point, Messi is struggling, he has to do everything by himself, but imo, a team will profit more this way (at least against weaker and midtable teams) since his actions are way more lethal than Messi-Neymar's actions.
Messi ALONE won't be good enough in CL semis and quarters.
But for La liga and for 80-90% of matches, I think that we will be fine.
In fact, we could be even better than last year WITH Messi-Neymar.
A paradox but...