Poor decision making again but we need his speed.
Luis, Messi and Antoine will not work. We need Dembele on the pitch.
Dembele was not really tracking back to defend during his 1st year. Then EV "thaught" him to always go back (in which he is quite weak) and try to defend.
That's fine.
Now (after his most recent injury) he comes on for a short time to replace Griezmann (who will be a flop on LW, because he is slow and can't dribble) and he immediately becomes a threat, even if feckes up two far shots. But there are always 3 Inter defenders trying to stop him, he makes space for the others. Fine, he made some bad passes, but all Barca players do.
Here comes the greatness of Valverde's tactical vision:
If you have 3 attackers, one is medium-slow, the other is snail-slow in every possible situation, the third is extremely fast, then which is the one you ask to go back to defend?
Obviously the fastest (Dembele) is the one who should NOT go backwards, he should be in line with the last defender, so in case the team wins a ball back early, he can run, even the goalkeeper could kick a long ball forward, instead of giving it to the defenders and then the team comes up to the box with 56 touches.
The very same scenario worked perfect in Neymar's time, and Barca scored a lot of goals at quick counters.
So whenever Dembele plays, he deserves a very different tactical handling, to utilize his pace, as EV's never working "safety net" would hardly work with him, as the coach wants.
EV did two changes, and this time both were good and progressive, but the fact remains that the max EV is capable of doing is to send players in, but the TACTICAL scenario remains the same.