I disagree with skimping on farms. Are you really going to risk starving and losing units over being cheap on an extra 2-3% of land?
Stables are meh, some love them some hate them.
As for 15%-20% guild thing, my kingdom is actually in the process of testing if there is a noticeable difference in spell durations with a couple of us running 15 and more running 20. You also have to keep in mind that in war your 15 turns to 12 and your 20 turns to 17 rather quickly.
Banks may not be necessary. I don't really believe in them since you are never at max pop in war so you never get to fully use them. With 65% draft you won't get great results out of them because your BE and peasants will be low especially if running 3+ wpa this early.
I gotta say that there is little difference between 1.5-2-3 raw tpa if you are dealing with legitimate A/Ts. They will see no wt and abuse you. My kingdom is in the process of warring a bunch of DEs. The ones with 5% or less WT are the ones right now regretting not building more. With NS being as powerful as it is, warring thieves without adequate thief protection is a death sentence for you.