At this stage of CRPGs and what most players expect in the gameworld, hiding [SPEECH] carries various problems with it. If we use New Vegas as an example, hiding % would have been infinitely better, going some way to preventing metagaming with magazines and reloading. Ironically, they actually did this for one convo (Legion spy), where it worked very well.
But if you hide [Success/fail] and even [Speech] as a whole, then there's no way for the player to feel that he is getting good (or bad) use out of his Speech skill throughout his playthroughs. There's no good indicator for whether he should invest more, and how much more, in the skill. This would only make sense if every dialogue line, or every significant decision made through dialogue, could be affected by Speech, so that you could tell 'organically', as you might a skill like Outdoorsman or Steal in FO1/2.
I'd think that a better way to do it is to keep [Speech] tags, but not success/fail (which should be bloody obvious anyway
) or percentages, and in important speech decisions, i.e. ones where you can get away with a lot or resolve an entire quest by speech, selecting the [Speech] dialogue option leads to multiple choices where you have to consider the situation and the personality of the NPC. For instance;
"There's no way I'm giving up the hostages."
" [SPEECH] Let's not be so hasty. There's no harm in hearing me out, is there?"
"Well, I suppose not, but this better be good."
(A) "You were once a soldier, and a good one. You might have left that life behind now, but you know what can happen when you drag innocents into a war."
(B) "The men out there are getting their orders from General George. The same one that once said negotiation is the first step towards defeat. Keeping the hostages will just push him towards drastic measures."
In ideal situations, (A) or (B) might then branch off to a second tier of Speech choices. This turns speech not into a single do or die check, but a conversation and negotiation where uncertainty and risk plays a huge role in your decision-making on whether to go for the biggest rewards or play it safe. It also makes you pay more attention to the actual content of the conversation and the NPC - you can't skip all the lines then hope to play a Diplomatic character.
The only downsides I see to these kind of approaches are that (a) you need good writing, (b) initially audience expectations will be broken, meaning some idiots will complain, (c) pure Speech Boys who think their high skill can get them past every firefight will find it harder. I don't consider (c) a big issue because the whining about can I beat the game without touching a fly is retarded - as for (b), you might be able to get around it with good presentation (i.e. hire Pete Hines, call it Radiant Speech =
)