The first thing I notice is that a lot of people thing that when you get a whole lotta hits something fantabulastic and ridiculous should happen. However we don't see that mechanic in other similar skills. What we do see are a couple levels of results that can be achieved with a different number of hits. Usually four, sometimes five.
As an example of what I'm talking about consider Assensing. You could make an adept that can put down twenty or so dice for an assensing test, and of course they could use edge. So maybe they get 10 hits.
What do they get? They get the 5+ result same as if they got 5 hits. That's the information that you can assence, you found it, good job, but that's all you're going to get. They get the "general cause of emotional impressions", not the whole backstory.
So in a social situation I'll generally have a couple levels of what someone could negotiate to, or what someone could be convinced to do at different threasholds. And then we'll see if you can get it.
Note that this isn't screwing the social adept over. They're still getting something for all those extra dice. Specifically they're getting consistency. If I have NPCs with 5 levels of thresholds that can be reached a super face can reach them regularly, and without edge. Same as any other specialist.
Of course they're also getting the ability to ignore ridiculous numbers of modifiers. As for that, well, welcome to SR4, it's like that with everything. Your sammie can probably do this:
http://www.youtube.com/v/zTYofGwUX6g&hl=en
If you don't like it do something crazy like have the modifiers change the target number instead of the dice pool.

Next is the "should a player be able to call a woman fat, roll a pile of dice, and have her love him for it?"
Well, to that I quote the rules. (If that's OK here)
QUOTE (BBB)
Etiquette can also be used to negate a gaff made by the
player that the character is unlikely to have made. In this case,
the player makes an Etiquette Test against a Threshold equal to
the severity of the gaff (1 minor, 2 medium, 3 severe, 4 disastrous).
If successful, the gamemaster should treat the mistake as
if it never happened, or as if the character was clever enough to
conceal it before anyone noticed.
player that the character is unlikely to have made. In this case,
the player makes an Etiquette Test against a Threshold equal to
the severity of the gaff (1 minor, 2 medium, 3 severe, 4 disastrous).
If successful, the gamemaster should treat the mistake as
if it never happened, or as if the character was clever enough to
conceal it before anyone noticed.
With players like that make judicious use of this.
The final thing I hear people talk about is role playing vs roll playing. Can they just not say anything and roll a pile of dice? Or, in the other extreme, does it just come down to the players charisma and social skills and the characters stats don't matter? Especially in the case when mister shy decides to become a face.
Well, for one if the situation is an extended one where they're just shmoozing a room or asking questions of lots of different people I'll often just roll the dice and then pick it up with the player when something interesting happens that deserves more detail.
But fundamentally I think less charismatic people should be given a shot at being a face, but they need to be encouraged to try to come up with something. Personally I just give them a little time to think and don't shush the other players who will tend to start trying to give advice. What they say as a player can affect things like what possible outcomes could be at different thresholds or I could apply it as a target modifier. Generally I cut them some slack as long as they're trying and getting better.
As for the silvery tongued devil who put a 1 in charsima and didn't get any skills, but likes to wow the NPCs with their own skills, I let them try and give them their modifiers, but their character will occasionally betray them (as the dice dictate). For example having them indeed say what the player does but while staring right at the females chest and then glancing over to stare at the waitress. So on and so forth.
That's just me. Sorry this got long.
EDIT: Thought of one other thing that's important. Sorry to make this longer.
Anyway it's important to remember that a number of the social skills also give you information. In the BBB it specifically mentions negotiation being used to tell if someone is lying, Perception+charisma being used to tell if someone doesn't actually belong, and ettiquite+cha to figure out what is proper in a given situation even if you're new to it.
But really a BIG part of being good at these skills is the details you pick up and understanding what they mean. Giving this information to the players is important if you want to move from the abstraction of a straight roll to actually acting it out.
I think a big part of why a lot of faces have a problem is they are faced with a blank, faceless entity and told to come up with something smooth. Whereas their character may well notice things. For example a skilled boyfriend will notice when the girl he's out with is occasionally glancing at something, has them walk by a certain store a couple times, or will notice if the subtly mentions something. Less skilled ones will miss it (personally sometimes I make it sometimes I don't, they're sneaky). Also after getting married I assure you that shopkeepers know to look for new wedding rings(that are fully shiney without scuffs) as part of their negotiation skill.
So maybe tell your face, and only the face, choice tidbits that indicate just what to compliment the Johnson on, or tell them which NPCs are only pretending to like each other. As dice dictate. This will give the player something to work with and make the role playing flow much better.