TTB, if you're still here, let's move the conversation on the figure skating thread here.
Playing Normal Mode as Satsuma (can't play Legendary at this point, it's too much.). I can manage fine with attack and defense, but when Realm Divide hit, oh boy. I can safely say: I REALLY DON'T LIKE THE ONE-SHIP FLEETS THE AI SENDS OUT TO CUT OFF MY TRADE LINES. AND ME NOT BEING ABLE TO DO NAVAL BATTLES WELL DOESN'T HELP.
...And they can move everywhere, while I have a problem chasing them down. Also, they send powerful armies on my territory. I've restarted the campaign twice because of it. I should just lay off on the capturing and wait to build up my tech tree.
On the plus side, I love how agents are useful now. And the foreign veteran's lines are funny.
I don't have much time to play, so I'm still under 20 turns with my Tsuu campaign. It's hilarious how much the AI on VH (the only difference between VH and L is no manual saves) spams levy infantry, I smartly teched up to line infantry and they reload 7 times faster (35 vs 5) than levy inf, almost 10 times faster with Inspire ability. One of the keys is to ATTACK OFTEN, because the AI is stupid and they will sit there mostly if they are the defending force, so split your army into 2 parts, melee in one part, shooters in the other, if the AI doesn't move, then attack his flank with your shooters so you can 2v1 or even 3v1 at a time, since the AI is braindead, you can even wait for Inspire to recharge in between advances. You can even angle your shooters to shoot DOWN HIS LINES, now that is some crazyness, because it means 100% accuracy as his lines are oriented perpendicular to your shots. It almost feels like cheating... but hey if the AI can insta-create stacks of 2000 levy infantry (and oh boy do they!) and respawn generals endlessly, I say us humans can use a few tricks too

If the AI makes a V shape to counter your split, it's a little trickier but still possible to flank his units to death little by little. Remember the AI tries to mirror your force with his force in both position and orientation. Especially with fortresses you can keep your main army on one side, all of his shooters go to that side and wait, send any unit to the other side and you get a free gate burnt down. If his gunners for some reason run to the other side, scale the walls with your melee and watch his army evaporate as the shooters are forced to CQC.
The easiest though is if he rushes you, because he will almost certainly go all to one side, in which case your melee can charge his rear, or your shooters can shoot up his rear. In the extremely unlikely event a defending AI splits forces AND rushes you, run your melee around to tire his troops out but manuveur quickly so you can 2v1 the part thats attacking your shooters with a hammer+anvil manuveur, once they rout, you can 2v1 (or 1.5 v1) the remaining AI forces which are now suffering a huge morale penalty because of already routing allied troops.
I just put in an order to upgrade the farms of Very Fertile Omi, my first upgraded farm (lol such a contrast to Shogun 2 vanilla) everything else has gone to units (and the one barracks for them).
My last battle, and that I saved the replay for was
Me: 400 Line Inf + 300 Levy Inf + 450 Levy Spears + daimyo + heir/son
AI: 2000 Levy Inf + daimyo
I zoom in and look all over the field carefully and discover that one particular section of tree ridge is sloped so that many shots taken AT it from the distant field will go OVER the heads of the shooters. So the battle starts and all of my army rushes for it (it's in the middle of the map.) Did I mention half of my army is reinforcing and not here yet? hahaha anyway, I manage to get there (this is all in slow-mo btw) spead my shooters out as THIN as possible, no reason to bunch up into 2 or 3 lines, that's stupid, and they shoot shoot shoot.
But my spears? Hiding in the forest on the right, slowly hidden walking for 2 minutes while 2000 men shoot it out with 600 men to their left, methodically exchanging death, towards the weakling conscripts... BAM 400 spears crash into the AI's left flank, I order line inf to concentrate fire on that levy inf and it routs in less than 20 slow-mo seconds, the chain rout begins slowly though. Meanwhile MY left is in danger of being flanked, but my reinforcements come in time and strangely because the hill slopes upwards from 2 directions, they fire almost point blank into one another, which is BAD FOR ME, so I pull the gunners back and send the one spear that came with the reinforcements charging over the hill (they get free protection from the slope!) I spread them thin to tie up as many levy inf as possible (3), then manuveur the reinforcing shooters further left to flank the engagement position and fire into it.
TWICE I have to run my generals over to use rally (inspire had been used on line inf) to keep the spears from routing, they are only conscripts after all and outnumbered 3 to one AND getting shot at from enemy shooters further back (friendly fire hurray) AND getting shot at by my shooters (sorry spears, we'll try not to hit you too often). The enemy levy inf is so thick my shooters can't miss. The 400 spears from the right is down to about 300 but they are PLOWING through the AI's levy inf and making good progress. Meanwhile the AI General has joined the clusterfudge on the left and ran into my already beleagured spears

, eventually the routing chains out of control and a full 1200 of his levy inf turn tail and flee (SHAMFUR DISPRAY!), my generals chase them down, a few AI units rally and regroup momentarily my line inf is advancing and blows them to shreds, making them "shattered" instantly. In the end my generals each get almost 300 kills chasing down the fleeing enemy. My generals are rank 4 already, but they never see any action (if I can help it), with so many guns blazing out there all it takes is one stray shot...
All but one or two battles so far have been like that. My force of 2000 meets a force of 2000 and reduces it to almost nothing while losing a few hundred men so:
2000 vs 2000 => 1700 vs 150
1700 vs 2000 => 1300 vs 120
1300 vs 2000 => 950 vs 230
950 vs 2000 => 400 vs 470 etc.
(Thank goodness for the replishment bonus from Shih + Summer time!)
But yeah, I haven't built a single ship yet or even seen the ocean on the new campaign map so I can't help you with naval stuff.

However, this youtube user has some great tactics videos for Shogun 2, he's about pro level, and he's also running a Shogun 2 tourney at the moment, but be warned he is extremely prejudiced against firearms use. Still, he has great videos on tactics including 2v2s 3v3s 4v4s, other multiplayer, etc.
http://www.youtube.com/user/fishsandwichpatrolphew....