So basically the title explains it all but I will elaborate:
Tycoons have two categories of upgrades
Upgrades that make more money
Upgrades that expand buildings/maps
Is there a “golden ratio” or sweet spot where you have the most optimal amount of upgrades in cat. 1 in relation to upgrades in cat. 2?
Obviously too many from category 1 will result in a game you quickly finished and too many from cat. 2 will result in a boring game because you make little progression.
It really depends on your game, Mall Tycoon (Mall Tycoon - Roblox) is a perfect example on balance, in the game they have a lot of cosmetic upgrades and 6 stores per floor, you should check it out, it doesn’t seem too cluttered with either category of upgrades.
There is no “golden ratio” or any ratio at all to be honest. I have seen games which favor category 1 and others which favor category 2. Favoring category 1 is not ideal because the tycoon will finish quickly, unless you wish to implement a rebirth feature, but this is a whole other topic. Favoring category 2 often causes a game to be VERY boring and disengages the user from playing or makes them AFK all the time. This is especially true if there is no interaction between other players. My recommendation (more of a preference) is to try to get half and half, or a little more of category 2. I personally love tycoons which give the option to buy all money upgrades and generate tons of money for other purchases, while also having the option to go for the austhetic path. This is just my opinion, but I feel balancing the two is important to keep both players engaged and also not make it a way too quick tycoon. It should not be very quickly finished, but progress shouldn’t be very very slow.
