One thing that has little focus in the Pipedrive ecosystem is customization of sidebars by the user.

Users can change the order of existing "system or app generated" sidebar panels and turn their visibility on or off. But organization admins are unable to create custom app panels from the settings UI in order to more logically group fields.  With more flexibility on the (custom) field side of the house, the ability to actually organize this data for end-users is significant. 

Sure, this is possible using API and scripting - but not every PD admin is a developer nor should he/she be forced to hire a developer to add a basic level of customization. 

Some examples:

Let's say you have a high number of account fields - you may want to separate in BASIC vs ADVANCED and group fields accordingly. Or let's say you record fields on a specific topic - like 2019 Revenue and 2019 units sold (now - there's another case for locking of custom fields as well) - maybe you want an app panel that is called 2019 Performance. I am sure people have many different examples giving their business flow and sales process. 

Admins create and organize by dragging fields into it, users show or hide in the UI the way you do it today.