* England and/or France opening to the English Channel in S01
I have seen this in the majority of GB games I've observed/played in lately and I just do not understand what is going on here. Every time this has generated significant mistrust between England and France, and I think in only one case out of the five that I saw did the power entering the Channel actually have ill intentions for the other. This has overwhelmingly been used as a path to make a power play on Belgium, but Germany has ended up with Belgium by the end of 1902 in nearly all of those games.
I am partial to other openings as both powers -- with England, I like opening to Norwegian Sea / North Sea / Edinburgh, and with France, I like opening to Burgundy with support and Mid-Atlantic Ocean. When I do open to the Channel with either power, it's because I am absolutely going after the other power and will order an army toward the Channel for convoying purposes.
I don't get why people "hedge" by going to the Channel but NOT setting up a way to attack the other power with it.
* Germany supporting Russia to Sweden in A1901
I have seen this play a lot in these games, and I love it.
The German-Russian situation in gunboat is much different than in full press. In full press, Germany can extort Russia with Sweden and compel Russia to take certain diplomatic stances and angles. In gunboat, the lack of press eliminates that option, and eliminates a lot of nuance that Germany can exploit with the option to bounce. Your options in Denmark in 1901 are essentially:
(A) punish Russian aggression in Silesia or Prussia
(B) stick it to Russia and bounce him without provocation
(C) explicitly signal to Russia that you're going to be her friend by supporting him into Sweden
Furthermore, because of Russia's relative weakness in gunboat -- unable to coordinate with her natural ally Italy, unable to mount meaningful offenses against Austria or Turkey without someone else deciding to jump in on the fun -- Germany essentially has all the power in the relationship. If Germany wants Sweden for himself, forcing that issue isn't hard, and Russia has very little meaningful recourse.
However, what I noticed in games where Germany DOES bounce Russia out of Sweden is that as the games progress onward, it's England who ends up with the advantage in Scandinavia. Allowing the English to maintain a foothold in Scandinavia is a scary prospect, since it's very hard to kick the English out once they're established with a 5-6 center base of operations.
If Germany DOES allow Russia to have Sweden, then Russia seems to reciprocate most of the time with an army build in St. Petersburg (and especially if Russia got two builds or if Russia's starting army in Warsaw is stuck there due to bouncing). It's a natural defensive reaction to English presence in Norway that simultaneously starts an English-Russian fight in Norway almost every time, which usually ends with Russia taking Norway and not making any further progress, and England tying up a lot of units trying to get somewhere.
This gives Germany a ton of leverage -- they can attack France without worrying about England rallying to France's aid, they can attack England with France and try to knock England out early, they can turn on Russia and force their way into Scandinavia with English help (but from a stronger position than if they'd allowed England to get a head start in Norway).
* Italy attacking Austria in 1901
I've seen this happen twice recently and both times Austria absolutely skullfucked Italy for it. And I'm not talking "letting Russia and Turkey have the centers," I mean Austria actually counterattacked Italy and obliterated them. The problem that Italy has had with these attacks is that they just don't work unless you commit to them in S1901, before you can know whether Russia or Turkey are going to give Austria problems. Surprise surprise, in both games Turkey picked a fight with Russia and left Austria completely unfettered. Austria also went +2 in both games, once due to a pretty hot read (Serbia S Vienna - Trieste to counter Tyrolia S Venice - Trieste!) and once because Italy just haphazardly tapped Trieste in A1901 which got blocked by A Vienna.
Mainly what I learned here is that Austria is fucking terrifying when it's not checked by Russia or Turkey from the outset. I don't necessarily think either power must commit to checking Austria as a consequence, although perhaps Turkey should (Russia is in a better position to work with Austria, Turkey ends up cornered too quickly). But it does mean that picking a 1v1 against Austria is pretty inadvisable and waiting to see how things shape up is the smarter approach for Italy.
* Italy moving to Piedmont in S1901, whether as a feint or a genuine attack in A1901
I never really considered this move too much, but I'm starting to love it as I see it played out. France is never in a position to punish it (probably because of the Channel shenanigans, see the first bullet point), and if they don't have overtly hostile neighbors after the first turn, you can always swing into Tyrolia and pretend it never happened. But the tempo that France can lose from overreacting to this army (and it does happen) is huge, especially since the common opening is for France to be in Burgundy and Marseilles after S1901. Moving to Piedmont incentivizes Burgundy - Marseilles - Spain in A1901, which leaves all of France's units clogged up around the Mediterranean, but not in a position to counterattack you for your S1901 move, and also takes away the leverage that France gained on Belgium. That invites England or Germany to get frisky, especially if they saw your move to Piedmont and assumed they might have a friend, and at the very least makes it likely for Germany or England to get Belgium, setting the stage for a less explosive French game and buying you time to get things done elsewhere.
If I had to come up with one key takeaway from all of this, it's the following credo:
*** Don't attack first! ***
Gunboat players as a group are strikingly aggressive and proactive. I think the lack of press makes you think that you have to be, since it's the only way to send a strong message about your priorities.
But I swear I see so many promising games derailed in the first year, because a player put their eggs in the "Attack X" basket, and it turned out that the diplomatic situation was really bad for an early attack on X. Italy attacking Austria only to find Turkey opening to Armenia, England and France butting heads over the Channel only to find Germany supporting Russia into Sweden, etc. Your whole plan for the game can go up in smoke because another power understandably didn't do exactly the one strategy you needed them to do for your attack to work.
Gunboat games are almost always long grindy slugfests to 18 rather than quick sprints to the finish line, so there should be no reason to rush into commitment to fighting one power. All that does is give away leverage to another neighbor, while not appreciably speeding you up toward a victory.