I haven't played any of these narrative focused games like Fate but would like to. My players are very used to other more hands-on type of game where the numbers are plainly what your character is.
Now I would like to give Fate a try and Strands of Fate seems interesting to me. One of the problems I'm foreseeing (probably unfounded) is the scale of abilities, especially for low power levels. So a rating of 2 is average while 3 is almost at the limit of normal humans. So I figured that 3-4 would rather be average and 6 would be a high level normal human.
So doubling the scale would require some extensive but perhaps not complicated rules change. It would also allow some balancing if needed. Aspect would give a +4 but you could actually go as far as saying the specialty aspects (and some others) only give +3 if you wan't to rate them differently, perhaps Specialty aspects only give +4 on their ability but +3 if you are able to invoke them on others. You could also go as far as to give always a +1 for aspects if you don't spend a fate point (big strong guy is still strong even when it isn't important enough to spend Fate points on it).
This would also give a bit of a leeway on stunts or advantages (whatever you call them) so when a power feels a little bit to powerful as a +2 but lacking as a +1 in the extended scale you could give it +3, in between the others.
Now the biggest problem here is the dice. What would you do there. Throwing 8 Fudge die is a bit crazy in my opinion so a new die (I call it Grudge) with (+2, +1, 0, 0, -1, -2) would be close but that's a custom die. 4d6-14 or 2d6-2d6 is a doubling of the extreme method.
Here are some methods that I thought about: AnyDice
Now another problem is that I don't know if it's doable. Stress and other mechanics that I would need to think through.
What are the pitfalls and why can / can't I do this?
Understanding Fate in general
One of the problems in understanding Strands is the lack of the labels.
The standard fate "Ladder" is labeled:
(Taken from Fate Basics, by Michael Moceri)
The Ladder is inherited from FUDGE, later Fudge, by Steffan O'Sullivan.
The normal range is -1 (unskilled default) to +3 (Good), with a human limit of +5 (Superb). Starting Skill limits vary from +3 to +5, and some games (like Spirit of the Century) have a fixed "pyramid" of 1@+5, 2@+4, 3@+3, 4@+2, and 5@+1.
4dF is used in FUDGE and thus in Fate, with this -1 to +5 range in mind.
Note that difficulties are assigned by the approach of "what level of skill should succeed most of the time?" - pick the label that fits. Note that "most of the time" is 50/81 (61.7%), for rolling +0 or better.
In practice, Fate relies more upon Aspects than upon the skills, as aspects can be invoked after rolling, and Strands is no different here. (See p. 53)
4dF is fairly heavily centered, too. +4 is only 1/81 (1.23%), as is -4.
Differences From Standard Fate
No Labels. The lack of the labels has been criticized as the biggest deviation from Fate in several reviews, and as a strength in others.
Strands caps skills (starting and experienced) by power level; most others cap only starting skills. (p. 29)
Strands gives fewer aspects than many Fate games (7 vs 10+). This means less ability to overcome a given issue by invoking multiple aspects, as you'll have fewer that apply. (p. 29)
You won't break anything by raising the skill cap to +5; most Fate games cap even low power at +5, not +3, except during character generation
I'll note that Strands states that the cap applies even after creation, but can be exceeded with GM permission. (See p. 29)
Changing the dice: 4dF is a simple to read mechanic. Linear dice are, for many, a bad mechanic. The strong central tendency (+0 is 19/81, 23.45%; -1 to +1 is 51/81, or 63%) is intentional - you seldom perform outside that without an aspect or advantage. A +2 from an aspect means you can expect to overcome a difficulty one step higher most of the time, and only 5/81 will you fail something of difficulty equal to the skill.
So, until you see the system in play, you might not want to tweak it, because in changing the dice past 1d6-1d6, you break the underlying assumptions that Steffan built into Fudge, and which work for Fudge and Fate alike. (Strands already pushes that a bit with the low skill caps.)
Further, when you go to doubled ranges with 8dF or 4dG, you much more strongly centralize the results to ±2 (the doubled equivalent) to 71%... and +4 or more is still under 2%.
If you want more extremes, use 1d6-1d6 or 1d8-1d8... but realize, you'll have just nerfed aspects badly past 1d6-1d6, negating the whole core element that distinguishes Fate from Fudge.