The problems in midfield(that have been present for 2 years) have still not been addressed for me. A reinforcement in this area was vital this summer as far as I'm concerned.
Sergi Roberto will get chances now in midfield, that is one plus sign, but Iniesta isn't the man he once was, he can't perform at his best every week anymore and Rakitic is hit and miss, although if the Croatian can reach his best level again consistently, then that will greatly improve the team.
It's time to start giving proper chances to Denis Suarez as it's evident that he is a talent, who could improve the starting 11 and has even shown glimpses when he has come off the bench this season. He is always moving forward and looking to make things happen, which is just what the team need. It's now or never for him really, but the problem is, I can see Andre Gomes getting more minutes than he should be getting again and the fact is, he offers absolutely nothing and can't even pass the ball forwards. He is literally useless.
Luckily the Dembele deal was pulled off as I believe he could be a real star at the club. The fee was questionable, but with the market how it is, it was going to take something ridiculous to prize him away from Dortmund. The negative is, that he's still only 20 and while he can offer a lot in the present, he still has a lot to learn and too much weight can't be placed in his shoulders too soon.
Getting Suarez back to his best will also be important as his goals will be vital this season. Messi will still score plenty but given the lack of creativity in the midfield area(unless Denis Suarez plays of course!), the Argentine's playmaking abilities will be more vital than ever.
One positive is the right back position. Semedo looks absolute class and I don't see why he won't continue to perform this way. He's hungry, suits the style of play and has many years ahead of him. Vidal is also good back-up, so it's an area that is definitely stronger now than it was last season.
As for Digne, he can be a handy squad player to be honest. Alba is the first choice left-back, but Digne can fill in whenever he needs resting/Valverde decides to rotate. He offers depth, as does Paco Alcacer, who scored goals and linked up well with the the attack when he was given chances in his correct position towards the end of last season. Playing Paco on the right(like against Betis) is obviously not going to get the best of him, but he can do a job through the centre and could be a handy squad player. With this said, I don't see why you'd let Sandro leave on a free and pay 30 million for Paco when Sandro would offer as much(if not more) as he does.
Talking of depth, Deulofeu will offer that and I see his signing as being a positive one. He didn't play well against Real Madrid, but had a cracking debut in la liga. Dembele will obviously go on to become first choice, but Deulofeu will be a very useful player to bring off the bench to change games and be used during rotation. This is something Barcelona didn't have last season.
The centre of defence could have done with another reinforcement, especially with Marlon being loaned out. If Umtiti is injured tomorrow then the only other option after Mascherano, is Vermaelen and you can't rely on him when he has legs made of glass and isn't anything special anyway. Yerry Mina will join up with the squad in January and could well be a success in Europe, but January is a while away yet and there are a lot of games to play before then.
Depth is looking stronger in a few areas, but weaker in others. If everyone is fit, then there is still enough there to challenge for trophies, but if there are injuries in key areas then it could end up being a long season.