I don't know, it all just seems so reactionary going for Mahrez. There were signs on the 12th that the deal was slowing down and on the 14th Sam Lee had tweeted that City had pulled out. That's sixteen days between pulling out and going for another player and it just seems so unlike City after they've been so good with transfers recently.
Yes, reactionary. That's about a week or 2 weeks of unbelief. Sure, Sane's injury added the urgency but they apparently didn't plan this out all so well and now they need a guy up front. For the next month which includes league games, league cup final, FA cup game and CL games, they literally have only 3 players to play a front 3. If I were Guardiola, I would give City bosses ultimatum to sign someone today. If it was Mourinho you'd hear him talking about it. Barcelona went ahead and bought Coutinho, a cup-tied player, in the middle of the season although they had enough players to play there. This is how big clubs operate, this is how you operate too nowadays.
It's not how they think but they also have to adapt when they're forced into it. In our 2008 Champions League run we played Hargreaves as a Right Back against Barcelona in both legs. We were without Pogba for a good part of two months and had to cope with changing our system. In Barcelona's 2009 Champions League victory over us Pep used Yaya Toure as a centre back. It's not the first time a team vying for silverware would have to do a bit more planning.
You were without Pogba and that's when you dropped points in the league although you had depth to cover him. They don't have any depth to cover their front line without breaking up their midfield trio.
When Sane returns they will still be top of the table considering their lead
From what they say, Sane will return in late March or April. They will play a CL fixture, Wigan in FA cup, Chelsea and Arsenal (away) in the league before Sane returns. By the time Sane returns, they might not still be on top, or they could be neck and neck with you (and maybe even with Chelsea) if they get another serious injury to KDB or Aguero or Fernandinho. Maybe they won't but they could, that's risking it and it's bad management.