I know it was mildly awkward that having a different column count made the rows wrap funny compared to the default logistics UI, but it was amazing to be able to see 40 columns x 15 rows of logistic requests at once. 10x6 feels like I've lost an overview perspective on all my logistic requests. Will the options for window columns and rows be coming back?

The settings will be back. I mainly removed them because Factorio only lets you change the request slots by +/- 10 and i wanted to avoid what you describe as "awkward" ;)
WIP:

That's 40x15 slots and probably the biggest you can set it to on 1920x1080 before running into issues.
All that's left to do is changing the - and + button to add/remove at least a row.

I've added adjustable columns in the latest update again, the - and + buttons should stay at the end of an row most of the time, except when importing a configuration or when changing the displayed columns.

Thank you! ^_^

I know what causes the "awkwardness," but it's wordy to explain. One thing which might be visually useful is an indicator between every 10 columns. But... that's also visual clutter. Either way, thank you!