Retro skill based system

I'm trying to design a system where instead of having a single level for your character, you have a level for each skill. A "skill based" system, if you will. I know this has been done, and with some degrees of success.

So, my first thought is you can't have hit point inflation. You can't start with 100 hit points at level 1 and end up with... say... 200,000 hit points at level 50. You would have much less at level 50, say 150 hit points. There needs to be SOME increase, if for no other reason than to telegraph to a stranger what your highest trained skill is leveled to. So let's start there. You have no race or class, all characters start with 100 hit points and gain 1 point per skill point in their highest skill. Just for kicks, let's cap the skills at level 50.

When you start out, you talk to a series of trainers that give you starter skills for free. You have the skills to kick any level one npc's butt. Let's just arbitrarily create some skills: For melee combat, we have main hand dagger, dodge, and parry. For spells we have damage spell (keeping it generic, here.) and spell resist. We'll have all skills use the same resource pool I'll call "stamina" that starts the same as your hit points.

Ok, so you kill the low level mobs with your dagger, leaving the damage spell and spell resist at level 1 because you like to stab stuff. You're now at level 3 in daggers, level 2 in dodge, and level 2 in parry. Dodge and Parry didn't track with daggers because you don't always use them. If you always choose the easy fights (enough to get skill in daggers, but not enough to risk great injury to yourself.) your dagger skill will always be higher. The other 2 won't catch up until you start doing harder content.

So you're ready to tangle with the npcs with level 4 dagger skills. But what would happen if you cross the street and start something with the level 4 spell caster npcs? If you could get into melee range, you could get a really good hit rate because they have no defense against daggers, but at the same time, you have no defense against their spells.

All kinds of choices open up now. Do you tune the npc's to expect cross trained players? Some players would just charge ahead with one skill until something stops them, others would cross train from an early point. Of course, each skill gets harder and harder to train as you go, and the support skills become more and more important.

I like this simple start. You train skills as you use them, your hit points are never more than 150% of anyone else's, forcing damages down across the board. What keeps you from getting into a fully one sided battle is that you'll never hit, and they always will and for maximum damage (Albeit a maximum damage of about 50 per second.) You can learn any skill you want, but they all use your limited stamina pool, preventing you from from doing everything at once.