THE E/T
Your best allies in a game of Diplomacy are those that you don't share borders with. England and Turkey are the primary example of this; they share a common neighbor in Russia on one end of their frontier, the usual A/G as you approach Switzerland, and the I/F on the other side of it.
Clearly, a Franco-Italian conflict early on simplifies things for both England and Turkey: England knows that France will not be a threat in the near future, and probably not a big player either, and Turkey knows that Italy will not be looming threateningly in the Ionian.
It also makes things absolute hell for Russia, as it frees all four powers on the Russian frontier to gang-rush eastward for builds before inevitably turning on each other. France and Italy are the only two powers with whom Russia does not share borders. Russia would rather see France and Italy charging towards its enemies' backs than uselessly tangled up around Gibraltar. That's nice for the witches' mutual neighbor.
The A/G is probably the most unquestionably assumed alliance on the board. Or at the very least, the most unquestionably assumed DMZ agreement for most of the game. Good luck getting Germany or Austria to move to Bohemia in S01. But if they are turned against a neighbor, that's better than them being turned against a witch.
So what are our witches to do? England would like to see a healthy Turkey, and vice versa. How can they work towards their mutual interest?
Turkey is going to be the first to run into diplomatic obstacles that can only be overcome by force. Early conflict with Austria is likely, and if it doesn't happen, late conflict with Austria is also likely. Even before that conflict is over and done with, the natural Russo-Italian affinity will likely begin to pressure both combatants from the north and south.
So what can be done about Austria? Here's where things get complicated.
England doesn't necessarily have a problem with Austria, in the same way that Turkey doesn't necessarily have a problem with Germany. Likewise, England doesn't necessarily have a problem with Italy, in the same way that Russia doesn't necessarily have a problem with Italy. But it's always awesome for Turkey when Italy and Austria go at it. It's not so great for England, as it limits leverage on France and Russia, but it greatly simplifies Turkish diplomacy by enabling cooperation with Russia against Austria.
Meanwhile, England should sound the Juggernaut Alarm Bells and direct Germany against Russia while warning him and Italy about the true beneficiary of the Juggernaut, which isn't Turkey or Russia, but France, as the response pulls all of his neighbors East.
In any event, the best case scenario involves the action being directed towards the center of the board and the witches expanding behind it, with the last survivor in the middle getting to participate in a three-way draw. The worst case scenario is simultaneous Sealions and Lepantos. This type of game will probably end in victory for an F/I/R, an A/G/I, or an A/F/G.
So those are the witches. What about the trans-Gibraltar powers?
THE F/I/R
Russia and France are unique in that they are the only powers able to build fleets on both sides of Gibraltar. France and Italy both have access to Gibraltar, and neither of them borders Russia. This alliance enables both Gibraltar powers to declare a (usually unprofitable) mutual front closed while getting assistance from a mutual ally with a vested interest in keeping both of them honest.
The agenda is the same in both theaters: keep the witches and the central powers on each other while managing the conflict and collecting profits from the flanks. Russia should take Vie, Bud, and Rum, plus a number of Turkish centers (this includes Bul) equal to the number of southern fleets he has. The three Scandinavian neutrals - plus a German or English home center, equal to the number of northern fleets he has - also go to Russia.
It's in France's best interests that Italy pay his fair share to Russia, as well as Italy's best interests that France pay his fair share to Russia. Russia can't really afford a war with either France or Italy, but he can encourage a war between them if one of them isn't holding up his end of the bargain.
So what are our beleaguered center powers to do?
THE A/F/G
Germany has enough England and Russia to deal with without France. France has enough England and Italy to deal with without Germany. And Austria has enough Italy, Turkey, and Russia to deal with, even with France in Italy, Italy in Turkey, and England and Germany in Russia, without Germany. And he knows that he can't trust Turkey and Russia doesn't trust him.
Of course, Germany and Austria always have enough of everyone else to deal with without each other.
Central powers stick together, of course. And Germany should definitely do whatever he can to keep Italy and Austria from fighting. But sometimes Austria just needs to Stringer up and put a French belt around D'Angelo's Italian neck, no matter what German Avon has to say about Italy being willing to soldier up and take his twenty years with just Tunis, Greece, and Smyrna. And it makes it a lot less complicated for Germany to direct force against Russia if France can be promised a helping hand in the Med once England is done for.
Italy has been treated basically as a question mark and subject of persuasion thus far. Where DO the wild card's interests lie?
ITALY LOVES RUSSIA, THEN ENGLAND, THEN GERMANY (then France)
Italy has three neighbors: France, Austria, and Turkey. None of them want anything to do with Italy at the start of the game. France wants a DMZ in Piedmont, Turkey wants no Lepantos and a stab of Austria, Austria wants no stabs and a Lepanto. Austria is the only power likely to attack Italy early on.
Italy can handle France and Austria at the same time. An Alpine Chicken can give Italy the upper hand on both of them in F01 negotiations. Italy can handle Austria and Turkey at the same time while Russia gets an extra build or Germany completes his stalemate line. But France plus Turkey equals death. All three is quicker death.
So does Italy take Austria out first? Sure, if he thinks he's got a solid F/I/R formed, because his next target will have to be Turkey. What about a Lepanto? Same alliance, next target Austria because he'll have him surrounded. France? Russia won't like that unless he's friendly with England.
So what about an E/I/R? Italy gets the Med, England gets the Atlantic, Russia gets the center. Scandinavia is the major point of contention; this alliance relies on peace in the north. That might be difficult if Russia believes Italy has sold him out by attacking France.
England, for his part, sees Italy, Turkey, and Austria as essentially interchangeable. He'll be negotiating with whichever one becomes dominant. If Italy can offer to keep Russia peaceful, he might go along with the plan.
So, like, what do you all think?