It has nothing to do with social situations vs anything else. It is just a bad deal to take 'play pan flute' when you can take Bluff, Diplomacy, or Intimidate instead, and blowing skill slots on obscure things that never come up is just a sucker's bet, pure and simple. All your rigid insistence on a single game mechanic for things that are not equivalent does is DISCOURAGE character customization, not encourage it, and you haven't enabled players to do anything they couldn't already do.
FOR YOU!
I could show you a stack of my RPG characters going back to 1982- various editions of D&D, RIFTS, HERO, GURPS, Stormbringer...the list goes on- and most of them will have secondary talents, professions, instruments, art supplies, non-magical books, skills in crafts, cooking, obscure languages, etc., because for me, having those options was not a "sucker's bet", it was part of rounding out those characters. What they did when out of combat or adventuring informed me how they would react in certain situations (in combat or social).
Options are not a "sucker's bet" unless you think the only reason for a PC's numbers is combat/non-combat efficacy. Me? I'm digging deeper.
Look at Jean Reno's character from
The Professional- most people would stat that character as purely a combat monster. OTOH, my version would divert character building points away from combat abilities into horticulture and a couple of other things. Why? Because being a top-level assassin is
what he does, but his love for his precious potted plant says something about
who he is.
And I'm as interested in the latter as the former, so diverting those character building resources makes sense to me.
Example: one of my mire recent 3.5Ed characters spent the bulk of his skill points on Rope Use, Languages, History, KS: Architecture, and KS: Engineering- because besides being an adventurer, he was a historian/archaeologist.
I really honestly have to hope for the sake of my own desire to play with rules that I like that what you suggest falls on deaf ears.
Why?
How does my liking to pick up Underwater Basket Weaving or Obscure Tribal Burial Rituals negatively affect your ability to choose Bluff?
Is it the whole "choosing between useful and useless skills from the same resource pool" thing?
Do what was suggested to me: don't divert resources from that finite pool- just write it down on your character sheet. You won't be as good at it as someone who actually diverted resources to gain that level of skill, but your PC will be customized, and you won't feel like a sucker.