Since i did not find a suggesions-subforum i try my luck here.
I actually had the idea, that eventually there could be a skill for gardening ? Whenever a plant is finished it yields 0.1 skill
It would honor all the gardeners-by-heart.
Not sure if its possible at all to implement.
However you are correct in your last statement, without a very exhaustive implimentation that involves hacking the client, I doubt its even possible to put something like this into effect..
Unfortunately stuff for the shard comes in 2 pieces the client end and the server end.. where it is possible to add things at the server end, adding stuff to the client side is very problematic.. the fact that +nyx was able to do such an amazing job with the patch came with no small amount of ingenious hacking and workarounds..
a great concept.. but in all likelihood not possible.. Not technically impossible just very very very impractical to even attempt.
I've been an Elder Scrolls modder for awhile, so I bring this up:
It's stupidly hard, or impossible, to add skills to the game itself...
Or so you'd think. Take Advanced Herbalism mod for Morrowind into account. Since 'herbalism' couldn't be added as a skill on the skill tree, it had to be added via script. The shard already has various shard-only things, like insta-offering lockdowns when placing stuff in your house, bio-engineering, whatever.
Why not just make it so there's a gump you can call up to see your script-added skills, so skills still gain from the way you said, and is visible, but isn't on the standard skill list?