Not at all, you calculate the likely outcome of something then gamble on whether that outcome actually occurs ... the least likely the outcome is the riskier the gamble, but it has nothing to do with luck in my eyes. As I've said I work on the basis that luck is outside the control of BOTH sides in a conflict. Luck to me would be bad weather, an earthquake, an outside party unexpectedly influencing the battle etc. etc. Luck is not the enemy making the choice you predicted or hoped for or gambled on, which is what happened with Sickle Cut.
What do you define as luck, then?
To me, it's a combination of two things:
1) Low probability events happen.
2) Events outside your control break in the way you want them to.
Everything else can be considered skill.
Now, I happen to think Sickle-Cut was the right choice, simply because the greater economic and manufacturing capability of the Western Allies meant their "steamroller" strategy would have won the war for them in just about any other German strategy adopted, while Sickle-Cut was an unlikely chance which had the possibility of victory.
That doesn't mean that it was likely to work, or that the Germans didn't get very lucky indeed. It just means any alternative would have basically have been worse.
Similarly, I think that Barbarossa was the right choice for the Germans as of late 1940 - because they were basically gambling that they could beat the USSR by forcing it to undergo a 1917-esque collapse.
This did not, in fact, come off. But, while unlikely, it's possible - and offers the possibility of victory. All other German options basically involve either being invaded by the USSR, becoming an economic satellite of the USSR, or stepping down their production for want of raw materials and seriously impeding their ability to fight the war.
The best choice as of mid 1940 would probably have been to offer a peace deal to the Brits - a good one - but aside from that their OTL choice was similarly a good one. It was basically to gamble on the British peace faction being successful - which is by no means assured, but it does avoid the pesky "having to invade somewhere without a fleet" which would be hard even if your enemy also had no fleet... as such, it offers the chance for success.
And what does all this mean?
It means that the Germans decided on strategies the success or failure of which depended on factors entirely outside their control - the French high command's decisions, the political situation in the Allied states.
The superior choice (if you can get it - it's rare!) is to force your opponent into a situation where any choice is a mis-step. One example is what Wellington did on the Peninsula - he withdrew behind the Lines of Torres Vedas, and his opponent had the choice between attacking (which would be very hard because of how strong the lines were), besieging (which would be hard because they'd stripped the countryside of food) or leaving (letting Wellington come back out and harass him again, and removing the threat to Lisbon).
Massena had no good answer to that one. He would have to... get lucky
