As it stands now, some unforeseen circumstance in the field will necessitate a minor modification to the design. The contractor knows perfectly well what needs to be done, but instead of simply doing it, they will ask the designers to tell them to do it, so they aren't the ones responsible for it. The designer of course can't simply rubber stamp whatever the contractor says, so they have to spend time figuring out what the issue is and whether the contractor's solution is adequate. All that adds up.
You always want peer review, even for a minor modifications. We have a similar process called code review.
It's not bad, it's just more expensive than not doing it. Thus, infrastructure built today costs more.
Both true. But the interesting question is if and when the costs outweigh the benefits.
I don't know why you think proper change control is a bad thing. In both software and systems engineering you submit change requests that are tracked, reviewed, assessed for risk, approved and documented. You do this to create an audit trail to identify "how we got here". Any concerns? It's documented in the ticket.
Now when it comes to civil engineering projects, where bridges can collapse, you should WANT that kind of rigorous change control of tracking, approving, and documenting.
Yes, documenting change control requires more work, but it also saves lives and creates an audit trail in case of a grave error.