Alright, update to my Uesugi Hard campaign.
I left off right after taking Etchu and Sado (along w/ my capital), and right after Takeda declare war on my vassal (which I've decided to defend). I've successfully countered Takeda's invasions and took North Shinano, Hida, and Kozuka. That means I went from 3 province to 6 and Takeda was down to 2 (Kai and South Shinano).
This time, I went very aggressive and fought hard to destroyed Takeda. I went south to siege Kai and prepare another army to invade South Shinano. I captured Kai and Takeda requested peace. I instead counter-offer and ask them to be my vassal instead and they accepted.
Immediately afterward, Ikki declared war on me and I couldn't be happier because my South is safe for now, and I made alliance with Date in the East. My focus is to completely eliminate Ikki because I'm afraid of the religious difference. I redirected the army that was attacking Takeda and moved them toward Kaga. Ikki had only 3 provinces but for some reason, they had 2 full stacks with decent units (bow ronins mostly) coming my way. I quickly took a lowly garrisoned Kaga and build up more units to hold Kaga. What amazed me a bit was that Kaga had the Ikko Temple that also gives a Warrior Monk garrison! I used that unit against them when they seize Kaga and it was decisive victory. With their army down to 1 stack, I quickly went to Echizen and to take them down and deny them their precious bow ronins. I then took down their temple in Kaga and build my own Buddhist temple.
With that, I've got 10 provinces under my belt and for the time being no major enemies. Later on, it turns out that Takeda was a handful as a vassal, because soon Oda and Hattori wanted to take on that prick. However, it is more manageable and I'm finally on my way to victory.
Some things I've observed during playthru:
1) As some people have said, the east (Date/Ashina) is quite calm (at least on Hard), those two usually fight each other and leave you alone.
2) No matter how I play it, Ikko Ikki will fight me the moment I shared border with them (post patch they are also much stronger). Their temples also give bad public order to me because it was trying to convert my provinces. I find that I must try to eliminate them at all cost. The benefit is that I get Kaga and Echigo by eliminating them, which I proceeded to build my troops (Nag Sam, Monks, Bow Sam and Bow Monks). I rarely need any cavalry.
3) Once I've subdued Takeda, the south was also very quiet, with only a couple of minor clan (Satomi and Oyigayatsu being relatively peaceful). My biggest surprise was that Hojo didn't really do much and turtle in their 2 starting provinces.
4) Oda and Hattori are usually the more worrisome neighbors, and they are aggressive in expansion.
5) I found out that I can't spam warrior nuns. I guess they are borderline hero units... The cap for me was 4 warriors nuns. That sucks!
6) I can only get 1 Uesugi Warrior Monk hero, which I got relatively early because it's in the Chi-tree and the temples/monks can generate very high Chi rate bonuses. I'm almost at 100% research rate bonus with my 5 monks, 8 temples, and 1 Philosophical tradition.
7) Since playing Uesugi, I've naturally select monk-research in my Chi tech tree, which means my monk agents are the best I've ever had for a Buddhist clan (my previous Shimazu play, my monks didn't have any benefits from chi-research), but now I get >60% revolt chances. Using them will help win a lot of battles and even help wipe out a clan.
After this campaign, I'm undecided on who to play next. What do most people play next after their Uesugi campaign is done?