The most widespread use for temples, in vanilla, is to allow the construction of successive buildings ("town halls", above all others). Magistrates limitations imply temples receive little attention. Other buildings, which boost income, allow stability to be as easily improved as temples, while remaining useful during "stable" times. The mod aims to restore temple's importance, compared to other buildings.
There are two kinds of effects bestowed by the first religious building: a)
a stability discount and b)
the possibility to enable exclusive provincial decisions.
The nature of the most evident bonus granted by temples hasn't changed: while in vanilla they decreased provincial stability costs by 4, it's now 16. The new figure is determined by the average number of stability points generally required per decade compared to the average increase in income provided by marketplaces.
In income terms a temple's future value is worth 16 ducats for every stability level below three. Stability drops are now scarcer, although figures deviate drastically from player to player: in vanilla there used to be, on average, 25 stability hits every century — that number is now drastically lower, 8. So, while a temple used to provide 4*25, or 100 ducats of discount each century (generally multiplied by stability cost modifiers), it is now closer to 16*8, or about 128 ducats.
Since the mod generally invites players to cope with about 0.8 stability drops per decade, temples will thus provide about 12.8 income-ducats over a decade, multiplied by stability cost modifiers
. These can greatly vary but — for most nations, in the beginning — will amount to +35% stability costs. Temples can
thus spare the player from about 17.28 income-ducats every decade.
Let's consider an initial choice of whether to build a marketplace (reference building) or a temple. We therefore assume a low 20% production efficiency. Let us then arbitrarily decide on average provincial tax and population (1.5 units produced), featuring a medium priced good (wine @ 13 ducats).
A marketplace will increase annual income by about 0.4 ducats, or 4 ducats every decade — well below temples expected return of 12.8 ducats. Marginal trade income increments may also be added, provided the owner has merchants placed.
Fast forward to the middle game, when production efficiency reaches 60%. A marketplace, under the same premises (price, good, production units), will increase annual income by exactly 12 ducats every decade — comparable to temples' 12.8 ducats (unmodified).
The trend is obvious: the higher production efficiency, goods prices and population (among other things), the more advantageous marketplaces are, compared to temples. The fewer stability drops one incurs, the more interesting marketplaces become, in comparison.
In vanilla, temples' 4 ducats every stab hit were distinctively inferior to 4 ducats every decade for marketplaces (without counting increased trade income from larger trade centres). It paradoxically always
made more sense to invest in marketplaces to recoup stability — especially given the magistrate expenditure.
Let us review some non numerical aspects. These also need to be taken into consideration to fully compare the two buildings:
A marketplace can determine whether a centre of trade will burst through the next level, providing additional taxes. Likewise, marketplaces increase compete chances for mercantilist nations.
Old temples provided a slim advantage tax wise: they sped up stability increases and thus indirectly granted an additional month worth of taxes — sometimes even census. Temples now also feature a distinctive provincial decision: "Institute Charitable Organisations". It is discussed in its own section.
Lastly, we shall end with this thought:
The most acute players will invest in temples once they can anticipate stability investments. Given the limited number of random events, it will be easier to do so in the mod. It is quite obvious: a temple will be of little use during those "stable" spells, whereas marketplaces, constables will continuously contribute to one's wealth.