Madrid and Barcelona situation cannot be separated from injury problems, most recently Barcelona lost Lewandowski who suffered an ankle injury, follow Raphinha, De Jong and Pedri who were previously admitted to the treatment room due to various injury problems. Madrid also experienced the same thing, maybe a little better than Barcelona, because only Courtois, Militao and Arda Guler were injured. If both clubs have full squads, El Clasico will be presented ideal this season.
Barcelona's injuries are worse than Madrid's. With Vinicius back Madrid look stronger. Courtois got injured and Madrid got a replacement. If his injury had happened after the transfer window was closed Madrid would have been in trouble. Militao is the only injury that Madrid has right now that would be missed. Arda Guler has never played for Madrid so we can't say he would be missed.
Barcelona on the other hand have four out of six of their midfield and attack out injured. Pedri might be back before the classico but Lewy, Raphinha, and Frenkie might not be available.
I would have loved all players of both teams to be available so the Classico would be more interesting