picking up WWN after forever w/ dnd

hey all!

i've been DMing DnD exclusively since i started about 15y ago. long story short, my players and i have evolved, i think it's time for a change for my GMing style, and i know some people i often game with are interested in the old-school feel too. i've spent all week with the WWN free (?!) book and also with the Diocesi of Montfroid setting. i'm very excited to whip a party together and get moving.

however, while i've done some old-school things with my DnD GMing, moving fully away from a plot-focused combat-heavy campaign to a more flexible sandbox just doesn't quite add up to me. i think i've narrowed it down to 2 big questions, especially for anyone who has made a similar switch:

1) what do you think are the biggest at-the-table differences between modern games and OS(R) games are? what are the biggest adjustments i should make as a new-old GM?

2) how would i convince a player that skills like Administer or Work are worthwhile? or, maybe more precisely, how do i get players excited about solving problems with Administer rather than kicking in the door?