The current method of aiming a searchlight is awkward at best. Perhaps the aiming method used by Create for it's weighted ejectors could be used? Shift+right click to set the target then right click to place the light.

While the current aiming method is awkward indeed, I wanted to keep it feel vanilla, and so far the current implementation feels more vanilla than anything else I've seen or could think of.

I understand. Another alternate method I thought of is after placement of the light another right-click will aim the light at the block the player is currently looking at. I think that would feel very natural and realistic.

something like a remote will be nice, with 2 modis, one that just set the lightblock new to the position of the player and one that update all lights / recalculate them in a specific range.

This here was only possible because I used a building wand with a grid system:

its impossible to "aim" the lights to the floor, because the ceiling is so high, you have always the problem that the lightsource block is then in the air.