I guess we've been seeing different games. The new signings are having a hard time adapting. Apart from Umtiti, and somewhat Digne, the others are yet to actually make a difference in strengthening the team, or being a sub that can change a game.
Only signing who is having hard time adapting is Paco. Umtiti has surely been massive upgrade vs last season Mathieu, Digne i cannot even how massive upgrade from Mathieu/Adriano. For midfield we didnt even have any real options apart from the starting 3 of Iniesta/Busi/Raki (partly due to Rafinhas long injury of course and transfer ban). For strikers same case with MSN. Big reason of our spring collapse was down to lack of options in the first half of season. Everyone just got tired and out of form.
This season we have 2 decent options who actually get alot of gametime in Denis and Gomez, sure they havent been gamechanges, but have not really flopped as well.
Rafinha/Arda have been pretty excellent when playing up front, we can rotate at back and not fear in games if Alba is injured. This all has made gametime split between players much more equally, which will eventually result in players being much more fresh in second half of season, which is when titles are actually decided.
And no, i also would have preferred an older and established player for striker sub, someone like Super-Mario or Van Persie or anyone similar. Paco is also young and needs alot more gametime then he has had so far.
Sure every player needs time to adapt, but young players like Sandro/Munir need to play as much as they can and having them stuck around for another season would have made no sense in any level.