I think it’s an interesting idea, albeit one that I think is unlikely to ever be implemented as a free early-game option.
I could see it possibly being something added for mid/late-game players, who have already hit Stronghold 20+.
More on that in a second.
It’s not really shocking, the existing buildings take many months (or over a year, without VIP) to level, so the addition of new ones are on a similar time scope, with increases over the buildings before them.
That said, many players involved in testing the Beta version have been giving feedback (myself included) that the current build times of the new buildings are too long.
More on that in a second.
Coming back to this: I suspect something like a paid Builder upgrade is an inevitability if the new buildings keep very long upgrade times.
It might not happen right away, but I think it would become a necessity to eventually offer newer players some way to accelerate building progress a bit. Starting on a 2-3+ year building process several years behind lots of other players would end up being too large of a gap, I think.
I think it’s a bad idea to end up in that situation, and have said so in my feedback shared with the game designers about the new buildings.
I think it would take the game into pay-to-play territory, and alienate long-time players who had to wait months or years for their building upgrades to finish.
If they were to consider a free version of that, where you could use building upgrades to research and develop additional or faster builders, it would really need to be part of the post-Stronghold 20 building expansion to not cause significant disruption to the existing player population.
But I’d rather just see them shorten the building times on the post-Stronghold 21 building expansion instead.