"Ahead of you, on a curve in the stream, is a stone bridge. A carriage is overturned at the far end of the bridge, creating a barricade blocking passage to the road beyond. Behind the carriage you see the tips of a dozen pikes above an equal number of gleaming morions. To the right, across the stream, just inside the tree line, is a hastily-built stone revetment, and behind it the light through the trees glints off the barrels of a half-dozen arquebuses. Because of the curve in the stream, the revetment is at right angles to the bridge, giving the arquebusiers a clear field of fire across the open ground approaching the span."
"Uh . . . I roll for Tactics."
"The king's minister, Enfou, pulls you aside as dancers swirl to the musicians huddled in one corner of the ballroom. 'The king is desperate,' he says. 'The baron de Bauchery can raise enough mercenaries to defend the frontier, but he refuses to do so unless he the king promises him Princess Pinkflower's hand in marriage. Meanwhile the conte di Grognardo is the best commander we have, but he refuses to serve under de Bauchery, and he wants the princess' hand for his son.'"
"Uh . . . I roll for Diplomacy."
Your skills are used to resolve your attempts to accomplish a task. They don't do your thinking for you.
In the first example, you need to decide how the adventurers are going to get past the soldiers holding the bridge, and in the second you need to figure out how you're going to resolve the conflict between the courtiers in time to get the soldiers to the front. Your skills resolve how well you accomplish what you set out to do.
Moreover, social skills are not
charm spells. A Helpful non-player character may be willing to take considerable risks on behalf of your highly diplomatic character, but that doesn't make the npc a thrall. The npc will still look after his interests and pursue his agenda while offering assistance to the adventurers.
I've used rolls for social interactions in every game I've ever played, from the Charisma-adjusted reaction rolls and loyalty scores for henchmen and hirelings in
AD&D to the Contact rules in
Top Secret to the social skills of d20, and in my experience they neither inhibit roleplaying nor do they result in the players substituting skill rolls for actually having to figure out how to best use those skills to get what they want.