KDE is in the road to be a semantic desktop, that's really ok, but what if I don't want any of those features?
I just want a very fast desktop like I'm used to, please make it easier to turn off nepomuk and family, they're so melted in the system that you almost have to hack it to kill the process.

No hacks are required. There are two checkboxes in the "Desktop Search" control panel that do exactly as you need: disable both indexing and semantic features (notice that they aren't one and the same).

The Semantic Desktop is still largely optional - unless you need KDE PIM - as Akonadi requires it. Other applications such as Plasma (activities) and Gwenview (tagging) will degrade gracefully as far as I know.

are there any plans to make the akonadi stuff independent of the semantic desktop?

Right now the akonadi and sematic stuff is a total killer feature.
But I mean it litterally, I had so much trouble with both of it, they
made me try gnome again.
Please, please please get rid of the semantic desktop dependencies and kill akonadi as well. Or make it behave like it isn't there. Or at least make it work.

As far as I am aware, the intentions of the KDE PIM developers is to make the experience as seamless as possible.

However - due to the legacy of parts of the KDE PIM codebase (which dates back to KDE 2 in parts) - the variety of configurations out there is huge. As a result, the Akonadi conversions are not always going smoothly.

Most conversions can usually be fixed with a little bit of manual work however.