A random stat and a thought:
= Barca usually plays very poorly in seasons prior to World cups and Euros.
2016: Barcelona**, CL: Real Madrid
2014: Atletico, CL: Real Madrid
2012: Real Madrid, CL: Chelsea
2010: Barcelona**, CL: Inter
2008: Real Madrid, CL: Man Utd
2006: Barcelona**, CL: Barcelona**
So, on last 5 occasions BEFORE a World cup or Euros (2016, 2014, 2012, 2010, 2008), we won La liga only on 2 occasions out of 5 attempts (2010 and 2016), while we didn't win in a CL in none out of last 5 seasons before a World cup or Euros (2008, 2010, 2012, 2014, 2016).
So, according to stats and history, a tough season is infront of us.
Imo, 3 major things which may harm us in the next season are:
1. Messi and Neymar daydreaming about a world cup all year. This will be Messi's last world cup in his career (or at least in his prime. He will be 35 in 2022'). Also, a huge pressure will be on Messi (regarding Argentina and a World cup) both from his Argie fans and from football fans who will talk all the time how CR7 is better than him (due to 3 Cls lately and Euro 2016).
So, a huge NT pressure will be on Messi this year.
Neymar on the other hand, could also easily slip into a world-cup-daydreaming mode this season.
2. a 2nd problem is that a club's season is way shorter in years with a world cup/euros. CL final will be played early in May, while this year it was played in June.
This means that there will be way more Sunday-Wednesday-Sunday fixtures from January to May and Barca will play La liga, Cdr and Champions league all the time 2 times per week.
Now, since we have an MSN-crap, who don't want to get rested and benched even when we lead 7:0 against Las Palmas, it is quite easy to predict that our attack may be semi-dead and totally exhausted in March, April and May.
So, MSN won't rest and that will cost us again in a spring of 2018'
3. the 3rd thing is related to a point no2: a lot of our starters are older (Messi, Suarez, Iniesta, Busi, Raki, Pique) and they can't play 60 matches per season anymore and they need a rest and rotation.
So:
1) MSN could be tired due to playing all the time in a short season, plus Messi and Suarez will be both OLD and TIRED
2) Iniesta, Busi and Raki are also old and they will have less stamina than in previous seasons.
In general, older players play better in "longer seasons" without a world cup than in short seasons with a world cup.
So, we will need lots of rotations and benching of key players in winter and spring of 2018'.
A good thing is, maybe Valverde won't rate CDR as the most important trophy (as Lucho did) and maybe he'll play with reserves in a CDR and save us some energy for other, actually important, trophies like La liga and a CL.
Anyway, remember those 3 things.
They could easilly kill us in 2018'.