Otherwise you'll find yourself in my current situation.

My character's sneak skill is lvl 100, but every other combat skill is at journeyman. His current lvl is 19.

He should be almost at this peak at this point but it's still going to take quite a while to master those.

Although I don't ascribe to categorical statements, I certainly did plan my stealthy mystic archer with great care. The centerpiece was ensuring her main killing skill (marksman) increased by 3-4 every character level. Secondly, we ensured by the time marksman hit 100, that her key attributes were also at 100 (agility, intelligence, willpower - illusion is her 'back up' to the bow). The simple supporting skills like stealth and alchemy were, of course easy to level. Anyway, those goals were met, as planned, at level 19 and that is where she stopped leveling. By capping her at the apex of her lethality, we denied her foes from gaining more hitpoints - which helps ensure her lethality. This careful and deliberate process was approached from the same perspective that any prudent elf planning to survive in a harsh profession in a harsh world would perhaps employ. Not for everyone, but I've been simply delighted with the results.

In order to ensure our game remained challenging and the character developed as a true 'glass cannon', we never did add any points to her endurance or strength, and she usually adventures with a single digit armor rating. For RP, she is simply a very fragile elf who dresses for stealth, not melee.

Dedicated stealth characters are about the only ones I play that might get a melee major, just for that reason. As a general rule, I don't use melee majors, since they tend to increase far too quickly for my tastes. I've found that with characters who do a fair amount of melee fighting, that works out just fine so long as they have a combat spec, but with pure stealth characters, even with a combat spec, the melee skills do tend to lag just because they don't spend as much time hitting stuff with their melee weapon. That said though, a lot of my stealth characters still have a melee minor and thus have lagging melee skills, and that's fine too. It honestly makes a certain amount of sense for them to be more skilled at sneaking than at fighting, IMO.