A free level group address structure is great in allowing freedom of 4+ levels of group address organisation, but it is held back by a predetermined requirement that you need to define your group ranges (i.e. 1-256) before you can create your group addresses.
There should be the option in ETS to remove this requirement for setting 'range start' and 'range end' values if wanted, and instead, have the flexibility to create as many levels as you like, and as many group addresses under each level as you need.
As a very simple example, say you configure group ranges as below.
- 1...30 Lighting
--11...20 Relative Dimming
--21...30 Absolute Dimming
The moment you realise that you need to add in an eleventh group address into the '1...10 Switching' range, you need to either create another 'Switching' group range somewhere else, or try and shuffle all of the existing group addresses and group ranges around so that you can make more room in the existing '1...10 Switching' range.
If there was the option to remove this range requirement, and view the ranges as simply, 'group address folders', then the engineer need not worry about running out of range space, nor having to predefine them all beforehand.
Each time a group address is made, it could simply take the next free address, and move on, as fundamentally whether the address is "11" or whether it is "4056" makes absolutely no difference to the KNX device itself.