But then every other cell directly arround it would have to resize accordingly

Why?

Why can't I simply individually format the size of a cell. The cells above need not be touched and the cells below need not be touched.

Like have 3 normal cells at the top,
and 3 at the bottom, and then one cell the size of those three in the middle, combined.
As it stands now you have to merge three sells to accomplish the same task that allowing individual cell resizing to do.

That means you have to highlight all three, then right click the click on cell formatting, then click put a check in the box as it stands.

Whereas if you allowed selection of an individual cell, resize it, and make it so that it doesn't effect the cells around it, then that would be simpler.. just a click a drag method to achieve the same desired effect.