This house had all the gutters draining into 1 downspout.
There are quite a few in this area like this.
I noted the sheathing issue.
i believe the rule of thumb is something like 1 downspout per 25 ft of gutter.
The 2nd story gutters look fine, until you consider where they discharge.
:—) How many layers of shingles are there? (pic 3) Looks a tad bit thick. Honest only one.