I'm playing as Oda, Daimyo difficulty.
I'm only playing this campaign since I bought the game... Do a few battles then stop and restart it so I've had quite a few situations going on and I took some time before gathering my ideas together, waiting for this particular campaign to finish first (alright it's not finished yet but to me it is).
We're ending here with me having my main army bordering Takeda's northernmost territory (it's the peninsula of Noto but I don't recall what the game calls it right now). Takeda right now (Early Spring) only holds 2 provinces in total (the other province is the one south east of their northernmost province as the one in southwest is mine and it's the one where I have my main army) and has 3 armies... one just spawned, 700+ pts worth.
I have another army which is quite battered, in the center of the map which is a result of a combine-army option from 2 armies which almost completely destroyed what originally was Takeda's main army.
I'm now in no position to raise an army in the conquered provinces, nor to reinforce with new units those armies because the system doesn't allow it and, even though I am winning badly (the campaign had me win 3 battles consecutive with one being a major battle with excess of 10.000 men per side and almost 70% casualties taken by Takeda), the nearly vanquished Takeda, with just 2 provinces have raised this huge army which none of my winning armies can match, unless I raise a new army and bring it there to combine with my main army (I will obviously arrive too late).
Not content with that, the system has allowed Takeda to actually maintain 3 armies because I wasn't able to destroy even one of them in these 3 previous victories (I don't think an army can actually be destroyed). This means Takeda is actually besieging some of my home provinces and I am supposed to either lose to their uber new army or fall back, abandoning my conquests, to pursue lesser armies, very weak, that will always escape... taking losses in retreats but just never being destroyed.
It appears to me that there's either something not working or some unbalancement that doesn't prize conquests and offensive operations and, things being like that, the campaign which could be (should be) the main strong point of this game, suffers from a series of repetitive battles, whose outcome doesn't really give the edge to the winning side and are apparently without purpose.
The more you beat them, the more they appear unscathed... but you keep winning because of the experience gained by the units... until, eventually, losing units to garrison your conquests (and you can't replace them with new units : you can only raise new armies and then combine them with the existing armies) and inability to reinforce, will lead your army to be destroyed by far superior numbers (no matter the experience of your units, you will eventually be outmatched by units that attack you from multiple sides).
The system is so strict you can't actually have any armies different from one another as once you raise an army, most of the coins you have go to buy the initial units so the campaign tends to be repetitive since armies are almost always the same (unless you combine them but then you can't "mark" the enemy anymore so you need more armies to build a border the enemy can't pass).
Furthenmore, while the defender can combine multiple armies cornered in one province to lack of movement points (it's what you should do because if the enemy is cornered you can take coins from undamaged provinces: you mustn't let the enemy armies sneak behind you otherwise you must chase them all over Japan!), the attacker can't attack the defender from 2 or more bordering provinces and must attack separately.
To beat this huge Takeda Army... which shouldn't be possible to raise considering Takeda only have 2 provinces now, I'll have to attack with my main army (vastly outnumbered), lose and then hope my second army can win. Essentially by counting the army value in points, Takeda appears to be only very slightly in disadvantage but how is this possible if they only hold 2 provinces and I hold the rest of the map after winning 3 battles in a row (3 or 4 I can't recall)?
In the meanwhile the other minor (200pts) Takeda armies are laying waste to my domains because they can't be destroyed.
See? I win... and I can't complete the campaign.
I smash an enemy and I find it again merged into a new enemy army or besieging one of my provinces somewhere else.
I advance and conquer... and then I can't reinforce... and the enemy seems to be getting even stronger (this has always happened not just this time).
Just my thoughts... I think the whole system is beautiful in its simplicity and it's very solid but with some little tweaks and features it could be put to much better use in the campaign.

1) Armies should be destroyed when their value is too low (split part of the remaining manpower to the owned provinces).
2) We should be able to reinforce them (get money by looting so you have a seasonal income to use for that) in a way that the army composition remains historical (there are many ways to do that)
3) It should be possible to combine attacks from different provinces (make units come to the battlefield piecemeal like reinforcements and flankers do).
4) There should be a chance after a major defeat for the CiC to commit Seppuku.
The big battle I fought and won was a real blast.

I've only had 2 such battles so far since I bought the game and they are very nice to play. It's odd but I never happened to get to the 20th turn as the battle is decided much sooner than that.
Note: The LoS/LoF overlay actually hides the deployment area.
Note2: I think a unit engaged in melee shouldn't be elegible to receive a general.
Note3: I don't think the CiC can join any unit in the Campaign (not in this one at least). Apparently it's useless as in most cases he's too far away to even provide any bonus but I noticed that when the AI has superior numbers (vastly superior numbers) it goes for the CiC to kill him. In these cases the battle is already lost but I haven't seen any effect on the units that were still fighting.
Note4: In regards with the UI perhaps it would be easier for the new players to see the units' ZoC highlighted in some manner. Making use of it to know who to charge and where to move (to block an enemy from charging someone else) is a critical factor in battle.
That's all... for now.
