Hey Bulia! Happy now? :)
http://img67.imageshack.us/img67/5248/lpeiz6.png
You'll notice that I've submitted several proposals in one. I included them in one mock-up because I needed to make sure everything fits (they seem to, the current version is just about the same size as the toolbar for the selection and calligraphy tools).
The 4 components (which ones to be included to be seen are):
1. The Width x base unit component. If you set your base unit to 0.2 pixels for example, you can increment the width of the stroke in increments of 0.2 pixels with just the directional keys. :D
2. I'd like to see Mode there too, because I rather like the smoothness of the freehand tool in Karbon14. Instead of Karbon14's "exactness" and "combine angle" text though, I just called it "smooth", because it's pretty intuitive, not to mention short. :\ I'm not sure if it will get added, but I'd be pretty happy if it were.
For those who've missed it, the output of Karbon14:
http://img137.imageshack.us/img137/9927/karbon14px5.png
(for me, Inkscape's current output is closer to Curve with exactness of 5, not more)
3. The drop-down allows you to chose the behaviour of the line! Either a normal, simple line, LPE with presets, or LPE with clipboard items. Lots of fun, no? You can create a shape and make a true vector brush out of it! (example: you do a leaf shape, you copy it, and you start "drawing" it in various sizes everywhere on the file. Whoo-hoo! How pointless! Moving on)
Anyway, the presets drop-down allows you to access dotted lines for normal lines and pre-defined shapes for LPE lines (I'm naming them calligraphy just because. If you name them Live Path Effect or Pattern Along Path, most users will probably not get it...)
4. Finally, I wouldn't have markers accessible from the top-level. Again, this depends on whether people agree or not, but I find it handy when doing charts. Very.
Actually, I've just noticed that I forgot the "pattern copies" components of LPE. Aww geez. Maybe for Clipboard, there could be sub-modes that take up the place the Markers buttons would. Icons: - single instance of a small shape - single instance of a shape stretched - multiple instance of the shape along the path - multiple stretched instances of the shape along the path
Not as necessary for those pre-defined calligraphy shapes though.
Anyway, Bezier would get the same features as freehand, minus Mode and Smoothing.