In my mere opinion one of the things that is holding back WordPress for growing even more and reaching out more specialised markets is the lack of good means for continuous integration.
One fundamental problem is the difficulty that is to create custom fields in code, without ACF. If it was possible to create custom fields with ease with all or some of the perks ACF offers (again, I just wanna make sure that the phrase "with ease" is well emphasised) it would bring us one step closer to an efficient continuous integration.
Nowadays if you need custom fields (and who doesn't?) you need to go for a plugin, as it does the job a lot more efficiently. Chances are you will do it locally first and then you will do it live. So it's a lot of rework to do it in both environments, not to mention sometimes you forget a field or another.
Sure you could just copy the database, but if it's a busy website with a lot going on, such as people buying stuff every day or sending contact requests that get stored in the database, you don't wanna do that as you're likely to lose data.
It gets worse when you have a team of developers with their own local environment, a staging or uat environment and of course, the live environment. These are lots of hours you won't recover.
So if we had easy ways to create custom fields, deployments would be a breeze!
All that said, I think that would be something really good to have, I have only seen that on Silverstripe (and sure people complain that they have to code to have custom fields), but maybe WordPress could be smart enough to provide the lazy and efficient way, right?
