I have the same issue and I haven't found a setting to put it back to how I had it before the update. I do not like the smaller grid layouts because they are full of wasted space.
I really dislike the new 3 column layout. All my folders have gotten larger, and it is a royal pain to now get to apps as now they are not in the same place as my muscle memory has them. It tasks so much longer. Why not offer options Samsung! I am very disappointed and had I seen this post prior, I would have not updated my phone. Samsung fix this! Thank you for the post. If I see a fix I will contact you Hespy
I had no idea something trivial like this could be so hugely annoying for me.
This really inconveniences me while using the phone and hope UI 3.0 next update will support better grid layout in folders.