I think it's simply the difference that the original series were based on the actual memoirs of Jennifer Worth which did include some shocking topics. And the worst ones were never put into the TV programme, or they were toned down.
When they ran out of memoirs, they said they would use real memories from other midwives/nurses from the time but perhaps these were not really forthcoming, as they seem to have gone towards "carefully researched social issues" instead which makes it feel very crafted and because they don't have real experience to go on, they probably shy away from making up any actual incidents which would be jarring to a modern audience unless they have the option to soften it by including some reference which makes us contrast to how much better it is today, or some kind of contextual explanation from Dr. Turner or whatever. And also include whatever personal storylines from each of the characters which sometimes come across as a bit odd - I found the Phyllis as circus peformer for a night one from the previous series really bizarre - I couldn't imagine she would have been comfortable wearing that outfit in front of a strange man, and Trixie's relationship with the widowed bloke comes across as very soap like in the way they keep coincidentally meeting!
It doesn't really matter, as it's all quite enjoyable and interesting to watch regardless, but they definitely have moved away from the gritty reality of the earlier series which is probably mainly because they're not re-telling a real story any more, but instead telling a fictional story which touches on some real life historical issues.
I think it could have been very interesting if they had opened some kind of permanent forum where anyone who had experience of district nursing or midwifery or childbirth from the appropriate period could have submitted their experience and then they choose interesting stories to follow up, interview the person, and retell those real stories with all the little details it's really hard to make up but which stick with people IRL.