Even way back when.. you did have Secondary Skills. This optional system was a chart in the original DMG, IIRC. Up to DM how these were implemented.
A natural progression of this was the skill system in 2nd ed, where you did have a choice of developing a good handful of skills that had a game related use.
Your auto raise option does sound like the +/lvl bonus in RM ver. before RMSS. As this reminds me too much of THACO, saves, etc, I'm glad it was dropped in later ver. Heck, I don't even use the /lvl "bonus" for spell affects. You have to buy each one after the 1st, w/PP.
With all that said, I think it could work! It's worth a try and I'd like to hear about it. With 2 games that play 1/month, each, I don't have much time for changing rules or hammering out many new ideas. Players don't like change, mid-stream.
There are some ok rules, here and there, about choosing spells 1 at a time. I sort of like the SoHK Research method. This is akin to the old D&D "chance to learn each spell" for low Int/Wis casters. You could pick /spell like skills or give a discount, less picks required, for learning an entire List..
You could do the same for Fighters, Thieves, Rangers, whatever, to give them a chance to excell in their chosen prof. I guess you'd go over what they have in the way of prof bonus (to use an example from RMSS/FRP) and give them a break on picks from those areas.
How about using Adolescence Ranks (or x2) and pick 5-10 skills that you excel in. After choosing a certain skill, the cost might be easier, 2Ranks/1 "pick used", to advance that skill. You're already familiar with the concepts.
This way, you have only a handful of skills that you're good in and even less skills if you want to start the game as a pro in that area.
Just some thoughts.