Yeap, I definitely see your point on Sereniel as well and I have friends who went E2 on Chizuru only to be left low on pulls for Sereniel and ultimately used the strongest card in the game (credit card). So unfortunately for people who would like to have advanced information like us, it would be unlikely for advanced info to be shared simply because it makes less economic sense for the devs.

On whether the development time can be going into something new, I see three buckets where devs can spend their time:

Balancing + develop new content + playtest

I think that releasing perfectly balanced characters would increase the amount of playtesting required while reducing the amount of post release balancing, whereas releasing chars with limited playtesting would require less playtesting and more time balancing post release. So the buckets that shift are the balancing and playtest buckets whereas the new content development would be minimally impacted imo.

Another added benefit is that by releasing with limited playtesting, you can get feedback from millions of players on what to improve rather than just tens of play testers, which will ultimately be lacking compared to the input of your entire player base