Mr. Vader, I 100% agree with you.
I have made 2 posts on the sub in the past about ship paint jobs, and brought the topic up with my fellow Legionnaires several times. It just kills me that something so simple is so unobtainable without spending IRL money. I have played a few of the mentioned F2P games, and in the case of League of Legends I have spent an absolutely embarrassing amount of money on cosmetics. However, I spent that money before they introduced the new "chest" system, and when it was one of the only games I played

That game is free, though, and Elite: Dangerous is not. I have spent $60 on the game and the DLC, and I have spent an additional ~$30-$40 on in-game cosmetics. Some of them are pretty cool, like the Wireframe paint on my Anaconda, but some of them are just absolutely
basic.
To me, the system feels oh so wrong. I like how you mentioned the slider bar, as it reminds me of a point I have made in the past. I would not be opposed to them selling "pallets" of paint colors, and various "tiers" of customization on your ship. Example (shameless copy/paste of a
6 month old post of mine from the sub):
Level 1: Unlocks some base colors and between 1-3 patterns that allows you to distribute those colors along them.
Level 2: Unlocks more colors and another few (more complex) patterns that allows for more unique designs.
Level 3: Unlocks more colors and patterns still, and maybe some decals or shapes.
That was an idea I had 6 months ago, when I had just started playing. As a new player, the lack of in-game customization options was upsetting. You mean to tell me that I can enhance the drives on my ship to run hotter and dirtier, in order to make me fly faster? You mean to tell me that I can enhance my power distributor to recharge any/all of the different capacitors more quickly, or to hold more charge? You mean to tell me that I can enhance my FSD to make me jump an additional 5-20 ly (depending on ship and build)? You mean to tell me that I can enhance my beam lasers to transfer the heat my ship generates into my target? You mean to tell me I can enhance my multi cannons to tag enemy ships that are running silent with heat rounds, that make it harder for them to hide from my scanner?
You mean to tell me I can't paint my ship blue? What the %^$&
P.S. Your BGS guide has was the bomb, thanks for taking the time to make that for us all.