First I like your Ideas especially the last, but I have a few things to say.

1. That one Servant can produce more than enough food isn’t OP, as long as there is no need to let the crops and fruits grow (and having no specific time it needs to be harvested before rotting) one person can supply food for a lot of people. But implementing that even halfway realistic would mean, that every farming related upgrade would be useless for a long time before getting something from it and without a very good storage it would be even more useless for providing food, simply because it would need more time to grow the crops and fruit than it provides food for.

2. Focusing the mansion on something is basically something the player has to do him-/herself. If Maverik would implement a focus, there would be lost some of the freedom for the players. Also there are some players that enjoy being able to create something that could be called an arcology.

3. The last point would need to either have an additional shop in the guilds or a change in the prices in the reputation shop (alternatively a change to the rate one gets reputation). If the mansion-upgrades would be just added to the guild-shops you would need even longer to unlock the special classes or every upgrade would be unnecessary when unlocked.

 P.s. please excuse if it’s hard to read or if I did some mistakes with spelling or wording, English is not my native language.

My thoughts on it:  Maybe condense upgrades into fewer but more significant packages, with an emphasis of the mansion gradually moving away from generic tasks towards more specialized stuff?

EG:  The mansion starts with three broad tasks - Gather, Forage, Household.  Gather retrieves stone, wood, and a rare chance of something like iron or a better wood.  Forage is all about fishing, hunting, finding wild crops, and the occasional medicinal herb.  Household generates money and reputation, maybe a new servant - increasing the size of quest rewards through negotiation, escort services, accounting, socializing, ect.  There are no limits on how many people can be assigned, but you can't aim for specific items.

LV2 upgrades add focused tasks.  For example, the "Quarry" upgrade allows you to reliably mine stone, metal, and the odd gemstone. Tier 3 allows you to add options for seeking specific items.  An alchemist lab for transmuting stone into gold, for example.

Upgrades are not only for empowering players, but also to set a path of progression.  The game currently suffers from being a bit hard - part of that comes from having so many choices, it is hard to know which would help in the early game.  By having the upgrades route the player's goals, it should be easier to guide the player without tipping the developer's hand.

Was going to do a separate post about the new (Man) Upgrade sys, but maybe I should add to this one. 

-Crops "feel good" b/c mostly they're cheaper.    (which  they should be!)

-How can food possible be OP?!?   It doesn't do anything (just like RL!)  except help you survive!      (ok maybe make some gold if you sell)
-Besides crops, many of the upgrades are *WAY* overpriced, too costly to even be an option (DEFAULT mode)  in 1st 21  days.    The whole   "silk before wood" thing you mentioned is b/c the *WOOD* upgrade is *WAY* too costly!    (you could build a HOUSE for that much!)

-Mining Obsidian-- *GOOD* idea---hard to get/buy prev versions-- (not sure should B @ home)  *BUT*, 
shouldn't take Obsidian to mine it! *AND*  500 stone is beyond ridiculous!   (BTW mines need WOOD & metal, not stone)

-Cloth (cotton?)   shouldn't require STONE to plant a field.   (maybe wood/iron 4 tools, + cotton [seeds])

-Realistically  (since that was brought up)   Crops/fields should be close to home, but *NOBODY*   [I live in a farming area & father worked with them)  has a *MINE* close to home!     Mines should be a distance away.   (maybe *buy* a mine?)      [If silk is "farmed" then it would go with crops]

Fishing:   

Fishing @ Mansion:  says has 2 slots, but 1 is *ALWAYS* used,  (so effectively only 1 slot even with upgrade)
Vegies by comparison (also has 2 slots)  works properly, & both slots can be used.    (maybe something to do w having fishing before?)

"Builder Tools"  whole thing is *RIDICULOUSLY*  Expensive    (now past D35 on new version, & *NEVER* upgraded that,  *SO* not worth it!) 

Seems much more realistic to me:    

1) BUY mines.  (Gold)      Then maybe  *BUILD* mine  (ie,  wood/iron)     [Mine could be sold in Town]     {NOT located @ Mansion,  but somewhere close by}

2) Planting trees shouldn't require more than small # wood  ("trees")   +  maybe   5 iron for hand tools.     [the "slots" limits # of wood you can get per time]
Since other place only have 1  (or at most,  2)  slots,   makes sense to have MAX 2 slot "woodcutting" @ Mansion --    [not likely to have a huge forest by your house if you have crops/fields also]      So,   1,  or 2   "woodcutting" upgrades.        (unless forests are "sold"  like mines)

The whole "condensing" thing mentioned is a good idea,  *PROVIDED* it's logical.       (buying makes a lot more sense to me----after all,      I'll buy the [CHEAPER]  IRON mine long before buying the   [more COSTLY]  Mythril mine
Life is full of choices----they only become bad  when they're confusing/illogical.

Maybe this is the wrong place to say it  (mentioned different post)  but Need to have an Upgrade for 2nd DATE   (like you have for bedroom) .

Does *NOT* make sense:       [Mansion Upgrades]

-Hunting;    [option to raise chickens?   ;-)   ]    Mines;   [maybe sold in town?]

-If you're simplifying/condensing:     Woodcutting  (1st)  *THEN*   Magic/Iron wood.     [if you *BUY* mines & forests,  this isn't an issue]

Oh,  final note on "being hard"    (I did a separate post on difficulty of Default mode):       IMHO,   has nothing to do w choices:     (but current NEW Man upgrade sys is confusing & doesn't make sense! ----so doesn't help---- & is mostly COST PROHIBITIVE of being used [w/o cheating] 1st 21 days anyway )
Most places where I've found game toughest, is where had  "BAD LUCK"     (hence I *STRONGLY*  PLEASE  GOD NO DON"T LET HIM DO IT! )  Caution against adding in too much "luck" random chance/etc.        ***QUESTS***     #1   Place had bad luck.    (Esp 1st 21 days!)     Items needed that you can't find to buy   (& can't build/make at that point)   ***DUNGEON CLEAR***    Quests when you only have 1-2 fighters & 1 or no weapons.    ***LOW POINT QUESTS***   500/3= ~167 Pts.  PER QUEST PER GUILD!      Sometimes I don't  miss *ANY* quests----but they pay so little that can't stop GREEDY BANK  [500 pts EACH]  by D 28.  

Suggestions to make easier:    (sorry if off-topic, but difficulty was brought up)    
1)   INCREASE   Initial amounts.      (gold/slaves)       (OR make this an OPTION   [Amt starting gold;  1-2 slaves] )       [750-1000 gold?]

2) RE-BALANCE QUESTS so that every Quest pays at least 167 Pts,  and *NO* Quest pays less than 100 gold.    [many quests cost a LOT more than they make]

3) Somebody put a *GUN* to that *BLOODY BANK* & make them behave!      [100k to be repaid in 100 days, is *INSANE* even by modern standards!    This is supposed to be an older time      (no gunpowder even)   so things should be a *LOT LOT LOT CHEAPER!!!  ]       -->>>  A *LOT*  of the difficulty comes in the *INSANE* time pressure----right while you're still learning everything     ["Alpha" stage game,  NOBODY's an expert]        There's very little or *NO* tolerance for MISTAKES.    [wrong tool;   someone resting instead of working, etc]     

4)   Initial starting TOOLS.     (this would make more sense anyway;     Imagine cutting wood----w/o an AXE!)

5)  Another idea quests:    Option to *CANCEL*    [only 1 Quest PER GUILD PER TIME PERIOD is offered,  so if we get bad one we can't do,  Need option to CANCEL---get another one.    [I'm assuming S4P thinks 2 Quests/Guild is too easy?]       OR,    offer  2  (TWO)  Quests  PER GUILD.

The "DEFAULT" Mode is *supposed* to be an intro,  should be *EASIER* than most of the game, *NOT* harder.