Depending on how strange the subject is (hence having a higher skill check) that spend a surge could be well worth it.
The only hesitance I have is something that [MENTION=6696971]Manbearcat[/MENTION] brought up is where things might apply within a skill challenge ... ie there might be party surges at stake and spending an individual surge seems a good deal.
Well, sure. Part of my reaction is that stuff like Speak Without Words is really not a good 'power'. It doesn't fit well within the concept because language is simply a detail. The GM is going to convey information as needed and required by the situation. If the goblin REALLY has something to say, it will speak halting Common. This is really the problem with any informational facility that PCs have. Its true also of all sorts of Divination. So, in some sense I wouldn't actually build this sort of capability up in the terms provided here.
In HoML the rule is absolute, only conflict requires checks or resource expenditure (at least beyond trivial levels of resource, you obviously eat rations on the trail, but I use a system of tiered expenses where, much like 4e advises, you don't bother to track cups of grog when you're a legendary character). So, 'Talking to a Goblin' could be explained in narrative terms via Speak Without Words, or Comprehend Languages, but you wouldn't pay for it or roll a check. The GM might dispense more or less information or change what he describes depending on if your controlling Skill is better or worse, perhaps, but you'll always get by. If there IS a conflict, then something like this could be helpful, you might expend a surge to create the narrative opening for the goblin to help you instead of running away, creating a success in your challenge in return for that cost.
I'm not sure why that would be an issue in an SC. Loss of the check might generate surge loss which you are thwarting, but you are still required to make a check here, just not for the effect of the practice itself, more for how its use worked out.
I think skillful practices ought to be acknowledged as an extension of the skill system...
They ARE a 'skill system'. This is one reason I think they should generally just be held to succeed, or simply have a small fixed cost to succeed. Those who lack the practice can STILL make checks to achieve the same things. A guy with a high Insight can try to get the goblin to understand him, but it may or may not work and he can't just use it as a narrative explanation outside of a challenge. He's just not that reliably good, he hasn't PRACTICED this technique.
Mayhaps you are right but they do seem very connected ... perhaps as it becomes telepathy range 10 for martial types and based on perhaps Thieving or Bluff ability. Where as this one is based on Diplomacy or Insight
I think the scope and the flavor can vary depending on the situation. If its a level 1 heroic character and a goblin, then its just basic pantomime, some empathy, and practice. If its a Mythic 18th level character trying to talk a corrupted angel into doing one last sacrificial act for the good of all to redeem itself, well maybe that's a good bit more magical!
A fighter/ranger or rogue with diplomacy and ahem warlords which is the class that I think most evokes martial practices.
Though i admit insight and perception seem like alternatives for speech without words
Well, I covered this above. In a sense yes, but a more limited one.