All guess work, just like you told us last season how poor Neymar is and how Barca would struggle in '50%' of games in this period Messi is injured.
I wasn't impressed by Neymar till the end of the last season.
Neymar proved to be awesome.
On the other hand, I told for a bunch of (our) players that they are crap, and they turned out to be a crap.
You make mistakes sometimes, you are right sometimes.
Of course that this is a guessing game.
We can't know this for sure UNTIL we will actually have to play CL knockout rounds without Messi.
I love SN duo from MSN trio, but I am not convinced that they would lead us to trophies currently without Messi.
Regarding Neymar, he still can improve a lot.
He could turn into a guy who will alone bring us trophies, but he could also turn into an awesome guy but a guy who alone can't do wonders.
Imo, current team is built around Messi, and SN are his little helpers.
So it is not fair to "play" only with an SN dou.
So, for the end:
1. MSN trio is the best trio in the world, and anything except 2 or 3 CL titles in these 4 years with them, I will consider as a failure
2. SN (Neymar-Suarez) alone, with injured Messi, aren't good enough for CL titles
3. but in some other universe, if Messi would finish his career or get sidelined for 1-2 years, Neymar-Suarez with a new world class 3rd attacker, like Reus or something like that, could again be good enough for a CL glory
-- we wouldn't dominate like with Messi, but we would be one out of 2-3-4 favorites in every season, and we would probably win 1 CL each 3-4-5 years
So, I don't think that in GENERAL Neymar-Suarez are bad/not good enough.
But in the current world, where they are "a weaker" part of MSN trio, they are NOT good enough without Messi (for a CL glory).
In some other universe, with some new MSN-guy, they could be good enough.