There are definitely two intertwined topics being bandied about, so I understand the complaint about moving goalposts. One involves speculation, the other "Wild" speculation.
Addressing "Wild" speculation, i.e. the scenario where the Axis won in the West/Med in 1940 and concentrating in the East in 1941-42, and would the Axis have been able to prevail generally vs. the USSR: I think Bruno has been pretty clear that his opinion is the entire concept is too far fetched to clearly reason out how individual operations in the East would or would not have played out. That is a fair point. We can say, for instance, that the number of POWs captured in Tunisa were equivalant to the number captured at Stalingrad, and if those troops had been available in the East, it would have made a difference. To Bruno's point, something that probably would not have changed is the poor strategic decision making, so you can't guarantee that had the troops been available, they would have been used effectively or where needed. Again, a very fair point.
So that leaves the more narrowly defined speculation, i.e. did a specific action or operation have enough of a reaction that it impacted other fronts. Torch / Alamein did cause a reaction. Rommel was forced to retreat across Lybia and into Tunisia (rather than find a place to make a stand in Lybia) due to the Torch landings in Vichy North Africa. A mini-2 front "sub war" was developing that he did not have the resources to deal with. In response, the Axis sent at least 3 German divisions (including 10th Panzer) and 2 Italian divisions to Tunisia to bolster the situation. They had no intention of abandoning North Africa. If they could keep the US/UK fighting there instead of mainland Europe, so much the better for the Axis.
So in the narrow view, the question is whether 5 divisions (that were at least available to be re-deployed) would have made a difference at Stalingrad. I believe the 3 German divisions (especially 10th Panzer) would definitley have been useful had they been deployed in support of the Italians/Romanians/Hungarians. All three countries were weak in anti-tank capabilities, so the stronger German divisions would have been better equipped to handle the Soviet counter-attack. But to say they would have averted the disaster altogether is far too big a stretch. The Italian 8th army alone was hit by three Soviet armies. Five more divisions may have slowed the tide, but I don't think they could have stopped it.