Please answer whether p1 (Guildhall upgrade is possible from any level) will finally be moved to "Gameplay changes" or not?
Definitely not before the end of the WTC, to avoid confusion between versions.
We'll see what happens after that.
The ability to upgrade from any level was implemented for the following reasons:
1. Players can strategically play around a low-level spell - curse, blessing, blindness, forgetfulness, etc.
Currently, they are simply deprived of this opportunity.
2. Balancing the options for players. It eliminates the situation where one player has a slow spell in the Guildhall/scroll/Sanctuary, and the other player doesn't have it anywhere, and they go and lose on a strong guard because they simply don't have other options for building up their army.
3. It eliminates "forcing" the player, if the game situation requires them to upgrade to a 4th-level Guildhall, why force them to build an absolutely unnecessary 5th-level building for that?
Why strain yourself - collecting scrolls with scouts,
checking shrines in search of the most important level 1 spells (slow, view land and air), if you can get them in any town in 1 (maximum 2 turns)??
The upgrade isn't done for free; it costs money and resources, and it also takes a day to build.
In the early game, this is very important - you might not have time to build a level 6 or 7 building in the first week, or you might delay the Guildhall upgrade by one day.
And I've seen many times when a player doesn't upgrade Guildhall 1, but instead looks for the desired spell in a scroll, Sanctuary, or in the Guildhall of another town because it's cheaper.
Also, I would like to note that for most players, upgrading only after building a 5th-level building will seem like complete madness.