Against an average full scale assault by Germany (2 INF, 2 ARM, 1 FIG, 1 BOM), even with the Russia FIG in Egypt, the odds of a Germany win are a little over 88%. Just under 3% of the time, mutual destruction occurs. So in 91% of attacks, the Allied forces are destroyed, even with the extra FIG.
What the extra FIG does do is reduce the odds of Germany actually taking control of Egypt, down to about 58%.
Without the extra FIG, the odds are:
German win: 99.5%
UK destruction: 99.7%
German Control: 93%
So, I guess the decision comes down to what you are trying to do as the Allies, and whether or not your personal Russia strat can handle losing that FIG both to combat use on R1 (since it cannot reach ANY combat theater and still land in Egypt) AND to not have it for future attack and defense.
Also something to keep in mind… those FIGs are often the core of the Caucuse defense, and pulling the FIG out to Egypt, instead of having it in its “usual” spot in Caucuses, MAY cause Germany to slam Caucuses on G1, if Russia did not take Ukraine. And without the extra FIG, Germany would have a significantly larger force on the ground for Russia to try to kick out… plus an AA gun to be agaisnt against the Egypt FIG if it flies back to help re-take Caucuses on R2.
Personally, I don;t think the loss of the FIG is worth it to slow Germany down 1 round in Africa.
Oh, and it is not an off-the-wall move. A Russia FIG to Egypt is a failry common strat in Classic, among some players.