It does not excuse that shit show, but playing devils advocate here, our defending has been utter dross all season. Pep probably figured the team he put out, whilst having less crestivity, would still have plenty enough quality to put a couple or more past Lyon. Whilst at the same time not leaking stupid goals at the back.
Obviously he was wrong, at both ends of the pitch. Hindsight is s wonderful thing, but in hindsight most would say he should have played our best attacking side and that may have meant we dominated the game and scored plenty. But on the other hand, we are talking about City here. We scored 6 over two legs against Monaco remember, and we still went out.
Root cause of all of this is not replacing Vinny. With him, our defence was ropey at times but acceptable. Solid enough to allow us to do our thing and win it at the other end. Without him, we've been screwed. Playing Dino our best DM as a rank average centre hslf because the rest are below rank average. Walker is dross 8 games out of 10 and Cancelo and Zinchenko 10 games out of 10. Our entire defensive line up - Laporte aside - are simply not good enough. Arguably Ederson as well. Great distribution but nothing like a top class keeper when it comes to keeping the ball our of the net.
Just look at the games we've lost this season and the teams we've lost them to. Basically anyone who can defend a bit and have a go at us themselves and we've been all over the place. We only beat Real because they threw us the game with their ludicrous mistakes.