We must break our “drug habit” of believing that we MUST complete each and every event and that we MUST score each and every “special building” and that we MUST construct each and every special building in our city. No, we do not need to do these things. The fact is that very few “special buildings” are actually valuable enough to keep in our cities more than an age or two; some are not valuable enough to construct at all in some ages but might be valuable enough to construct in some eras. So resist the urge to buy into the hype and social engineering that Inno Games tries to sell you on — Don’t believe their marketing BS when then tell you that a building is “Special” or “Great”, these words do not mean “valuable”. The Colosseum and Notre Dame are both Great Buildings, and neither is valuable. The Drummer School and Color Guard Camps are both Special Buildings, and neither is valuable.
Ask any established player, who is near the end of their current age and does not want to get pushed beyond that age, how valuable it is to NOT waste C Map provinces or technologies on events. The game has changed to the point where there are now 1-2 events each month, plus we a weekly GE event. We ALWAYS have more chances to score more “special buildings”. So just get used to have pages upon pages of unused “special buildings” in your Inventory. Most special buildings are NOT valuable buildings. Any building that we choose to add to our city had better provide our city TREMENDOUS value-per-tile. This is especially true for “special buildings” when we must often research a tech and scout/infiltrate/negotiate/conquer a C Map Province, in order to score the “special building”. This is why we skip MOST "special buildings" in the game — most of them are not worth wasting a scouted province on or researching a tech on.
The Checkmate Square from the Albert Einstein event was valuable enough to even get pushed out of an age we wanted to remain in, in order to complete the questline to score the special building. There aren't many buildings in the game that can buff the combat bonus or our attacking army, where we will also keep that building in our city no, matter what age we are in (there are some late-era barracks that give attack boost but they all cost a lot of population and we might not want those units, and the Drummer School is not worth keeping for the attack boost).
An upgraded Maypole is:
A. small pile-o-happy, which is inefficient compared to other special buildings
B. small % increase to our coins production efficiency.
We have several options for A — GE spits out decos weekly that are about as inefficient as regular Maypole (I can’t find detailed happiness stats on the upgraded version). We also already have 2 readily available options for increasing our coins production efficiency: Friends Tavern boosts and St. Marks bonuses. Pushing StM up one just level above level 10 will grant a +5% coins production bonus, in 0 additional land. Pushing StM up just one level below level 10 will grant a 15%-20% coins production bonus, in 0 additional land. So we already have a very good alternative, which we are going to construct in our city anyway, to buff our coins production efficiency. By the time we own a level 7 StM, our coins production bonus is +200% and we won't really care much at all about using coins production bonuses from: the Tavern, the new boost bottles, or an upgraded Maypole.
Down in Industrial Age and lower, the total coins production capacity in an HQS city will lag significantly behind the total supplies production capacity. This is mainly because we construct a massive field of supply production buildings in much less relative population, and partly because we usually construct and level up LoA before StM. In the GB leveling order that I prescribe, I always list StM before LoA, because I know that total coins production capacity is going to hold back lower-age players from spamming more UBQs more so than total supplies production capacity. But by the time we arrive in FE, our city is going to own more ultra-efficient coins production buildings, such as: SoK, SoA, The King, The Queen (not the statues from this recent event but the older special buildings that are more colorful), SSWs, and Tribal Squares. And our city's total coins production capacity is not only going to outpace our total supplies production capacity, but it’s going to lap it. So in the long run, any version of the Maypole isn't going to have a permanent place in a late-game (PME and later) city, because we are always going to be looking for how to cram in our umpteenth SoK, SSW, a building such as the Checkmate Square, or Kiosk (I would love a whole row of Kiosks locked to PME and above), or more of the massive Terrace Farms for producing discounted refined goods.
If we had a single 3x3 plot of land in a lower age city, then using the upgraded Maypole for +8% coins boost would be valuable enough, provided we had a single 3x3 plot. But any time we can actually fit in 2 more Clockmakers/Alchemists, then those buildings will ALWAYS provide us much more value, because that is 7 more completed “produce supplies” quests per week, and also 7 more UBQs per week if we can afford them. More completed quests = More Loot in the form of: FPs, medals and goods, which are the reasons why we work quests. Any special building added to our city takes away total quests-per-day and is going to cost us all three of these resources.
We do not replace questing buildings, which help us score more FPs, medals and goods through quest rewards, with special buildings that only help us produce more coins or more supplies. The only special buildings that produce coins that we actually keep in the lower ages are the ultra-efficient coins producers such as: SoK; SoA, until we can replace it with an SoK; The King/Queen, until we can replace them with either an SoA or SoK; special buildings that add attack bonus like Checkmate Square and Speakers Corner; and the Ziggurat that provides very efficient population and enough happiness to make its own population happy (but not enthused). There are other special buildings that produce coins, which will become more valuable in the later eras (PME and later) because of their discounted refined goods production, such as: Kiosk, Oasis, and Tribal Square. But since we can quest so easily for goods in Ind and lower, we would not waste land on constructing such buildings down there.