I mainly feel that this will allow them to make bigger worlds agains, increase the population limit further, possibly increase the sims on zone limit and optimize the game better since they can focus solely on 64bit.
This slow down in productions could actually be because they have been planning this drop of 32bit for a while now and they only wanted to get what was near completion out. We may see an increase in releases after the update as I'd imagine all packs currently in production are being made with the upcoming update in mind.
This slow down also makes sense since they're still getting console caught up and if they kept releasing packs like they did before console would never get caught up.
Also bugs are a thing possibly on their mind. Since 32bit will be getting it's own sims 4 version that stops at strangerville there could be several bugs they want to get fixed before they release it and 32bit players stuck with whatever bugs are left.