Please define "design" - as one of the designers in KDE our task is monumental and spread out over different things: Plasma, Individual apps, Plasmoids, etc etc. All done by different people with different ways of connecting up and many which we have no way to control.

For example, when you say "theme" you are in fact talking about four different things - and that is counting low (I assume you mean, colour theme, widget theme, plasma theme and icon theme). Then comes which app you're referring to. Some apps use some layouts and movement patterns, others use other patterns. Or maybe Plasmoids. Or different subsets, login managers... the list goes on.

"Overall Design" sadly is too imprecise to use in this case.

In design there is a truisim in that complete control makes it easier to create unification in design and unification in design is key for ANY aesthetic. Now we cannot have "complete control" - because that's not how the KDE community function (for good reasons I may add) - but that is also a problem with design.

Currently we are going good - the design is the active, daily work, by a large group of people who at the same time try to ensure that others get the possibility to work together with us at all times ("community" being a very relevant thing to KDE). But it also means inspiring instead of ordering, finding small glitches and constantly looking towards a broader future goal while, for months working on implementing smaller details. There are design goals - but they can't be done in one huge step - they will and HAVE taken years to do.

Many in the VDG work professioally within design, from fields like visual artists, Art directors, usability experts, and one thing we all know is that working in Open Source - but more importantly working like we do in KDE, in the open, with an open door - is more complex than anything you can meet in other fields.

All that said: I would be lying if I didn't some times nourish the dream of going "screw this! I am making my own thing from scratch where we set the design at day one!" :)