About Nadal. Well, he's a very special beast to balance. Indeed the spin is high as its emphasizing well his shots in reality, at least those wich are very spinny, we couldn't decently give him the same spin as Ferrer, for example, and visually, Ferrer's spin pretty much looks like the real one, maybe a bit more than the real one. That's cosmectic considerations though.
Florian has good points about it, and some issues are indeed tied to TE mechanics. It would be a great feat if we could assign a different spin stat for each wing, as this would allow us to keep up with a great spinny FH, and balancing his wings better with a lower 40-50 spin on the BH wing, wich would be a weaker and more attackable side. Though this feature is not available for now, so we have to deal with.
The consistency is another way to tweak him, but it's far from a perfect one, because in TE, if lowering consistency influences shots depth, it also lowers the danger zone positionning tolerance, thus, impairs the defensive ball recovery abilities when hitting a shot on the edge, just in reach, wich is not nice regarding Nadal traits. Here again we're limited by the fact we can't shorten his shot depth too much without hampering also his defensive reach potential. Though we have to explore a bit more lowering also his counter stat (not sure it influences top spin b1's depth enough though, knowing that defenders have a depth bonus on those shots as Vmoe pointed out).
About the spin. Well, i agree high spin is difficult to deal with/attack in TE, especially when those top spins can be very deep.
But i'd say also that spin doesn't win all by itself. It's more a combination of things wich made Nadal that strong in 1.10 (but especially since 1.0f came out, 1.10 Nadal with 1.0e was'nt *that much* overhelming), 1.0f introduced an auto-step back feature, wich helps changing direction, thus countering noticeably the inertia factor, and globally inducing an overall higher reach, that's why we are in the process to reduce speeds, because this hampered the balance we had in 1.0e. A char with -3% speed in 1.11/1.0f shouldn't be slower (max speed will be lower, but overall reach shouldn't be

, that's the main objective) than he was in 1.10/1.0e. We could have lowered all chars speed, but we took benefit of this occasion to close the gap a bit between T1's and T2's.
The combination of things that made him too strong is speed (reach), power, and spin (along with depth).
But as an example, in 1.08, Nadal had the same speed stat, a higher spin (85), the same power stats (even a bit more @ BH), but he wans't considered as a good char, or not enough. With the same power stats, the 2% more spin was enough to hamper his shot pace enough to make people reluctant to use him. And in our personnal tests with VMoe,, we could still win a Federer vs Nadal matchup by those times. Nadal still felt to weak and that's why in 1.10 we tried to lower his spin to 83, and lowered a bit his BH power. Lowereing his pin made him much more powerful. That's just something i wanted to point out, because what's important is also the power/spin couple, not spin only.
At the same time we didn't had the same overall level of play among the tour by those times, but still decent/good players around. Players like Robbin can deliver a pretty solid level, and Spencercarlos defeated him 6-3 7-6 in Beijing, after US Open, thus, with 1.10 stats (and 1.0f). Also as pointed out Vmoe, Spencercarlos using Federer could take a set from Voja @ Paris Masters, that was still using a good shotmaker, on a pretty fast surface, yes. And more problems will araise on slower surfaces, that's why we reduced the speeds a first time in 1.11, and we may go a bit further with 1.12.
For now Nadal wings are noticeably weakened, power wise, though his FH is still a petty decent weapon. I think the top roster speeds are still a bit too high, we'll run more testing in the next weeks, and we can also play a bit with surface physics along with stats, to find a better balance.
If we can't find in the end an acceptable formula, we may also definitely explore another way, decreasing the high spinners spin range (68,70,74,84 currently) to some lower range, like something in between 55 and 75 for a start, step by step lower if needed, to find a better formula.
One thing that would be appreciated and definitely help, besides suggestions and / or complaints, would be also sometimes providing .dmo's, we'll not watch the whole thing every time, but that can help us along with our testings (it's very time consuming). It would also help if a player like Voja could sometimes play some Federer(or else)/Nadal match-ups, vs some solid Nadal, and provide a .dmo (i mean even as friendly matches, not especially tour matches, but you can find a good sparring partner, do some testings, mirroring your match-up, and provide a dmo and your feelings/opinion about it), because a char efficieny also depends on who is using it, and i guess Voja, even if Nadal probably fits his playstyle, may probably win also a lot of matches with different chars (though possibly not as easily than it was possible with 1.10 Nadal ) , like Vmoe did with Harrison and Wawrinka in different tournaments.
For now as you saw we're going for modifying/lowering his wings, along with the reach, if it's not enough we'll explore different ways, we're totally open to it and pretty aware of some issues. Balancing we'll never be perfect in any game, though we can always tweak it better. For now we had a better balance with 1.10/1.0e. Some core TE changes and you have to re-work it and deal with some obvious imbalances.
But the only factor : Voja is unbeatable with Nadal, though interesting, is not enough by itself to go for a gimp though, of course, knowing his level. Though it's always intersting to observe how a great mover can exploit such a char pushing it to the limits. If it leads to an impossible no match against a wall, on a reasonably fast surface, there is definitely an issue. Though also keep in mind we can't either tweak the roster only for the best players around, we'll have sometimes to find a compromise to please the majority.
We don't want either having only heavy hitters being able to hit thru Nadal, obviously, because what will happen to the poor average powered then. Though we don't want either the average powered T2 hitting thru nadal , and thus the heavy Delpo or Berdych *destroying* him

So, we may play with, speed, and possibly power stats (slightly increasing it for some T2's), and also surface physics, as an example, adding a bit more slipperiness (wich means more inertia) on clay can allow us to increase the winners potential / wrongfooting if needed.
There is definitely different actions and formulas possible to achieve different results, some of wich may end acceptable, almost "perfect", or flawed. And scaling down the high spins is one of the tools we may consider.