AbdulAlhazred
Legend
Well yes he evolves but it's 4e's limited multi-classing that makes it hard to model Conan's evolution without wholesale changes to his classes... thus my assertion that 4e wouldn't model a character as broadly proficient as him very well. At the end of the day D&D (all editions) don't really support single protagonist adventurers who can pretty much handle all challenges... Even with open multi-classing like 3.x your effectiveness suffers with the more classes you take
Well, this isn't really a 4e thread, but IMHO 4e can do it rather well. You have class, MC, hybrid, and then all the feats, PPs, and EDs to work with, as well as just a vast array of different power choices. Conan could start out as say a BRV (MP1) fighter, that would work quite well. Give him Nature (Maybe he MCs into Ranger) at level 1, he's human and gets an extra feat after all. I THINK that covers your low level Conan. He can then acquire some roguish abilities (all he really needs is Stealth, I don't recall him ever picking a lock or such). Truthfully he could just start out with the Rogue MC. While Conan was familiar with Nature it seems to me he didn't generally evince any deep knowledge about it.
Later on he could pick up some fighter powers that provide some level of leader ability, maybe retrain his MC into warlord to get a Battle Captain PP or something. Alternately he could just start out as a Hybrid Warlord|Fighter with a Rogue MC or something like that if you want to get fancy.
I think there's sufficient scope within the bounds of 4e to do it. My only complaint with 4e is that it demands a fair amount of rules awareness to have a decent handle on what the options are and how they can best be employed. Also with a character like this you get the sort of "plan it all for 30 levels to get it right" effect, but then the game wasn't really designed to EXACTLY reproduce a specific character, its always an edge case.
Tying this back to 5e though.... I think 5e, for the most common use cases, has succeeded pretty well in allowing for generally creating a character sorta like X concept. You make a few pretty broad choices and you get mostly what you want. The problem is it lacks some sort of way to fill in the blanks from there. You can take feats, but it really is much less flexible than 4e was, especially later on. Its also annoying that you have to start out as this sort of 'rump' version of your character concept. In 4e you might need to fill it out and evolve it, but you have your signature from day 1. If you want to be a magic-wielding fighter in 5e? You have EK, but you have to wait a couple levels to get it. Nor does 5e's ala-carte MCing system seem particularly well-conceived. I would MUCH rather have seen something along the lines of PP/ED and maybe a "steal a bit of another class' shtick" line of feats instead. It would have removed the need for the silly 300xp band 'level 1' that only exists to stop cherry-picking MCs and is an optional system that twists the whole game's design.
Beyond that, on an unrelated note, I just don't like 5e's AD&D flavor. We did that to death. I really appreciated the much more free-wheeling heroic action figure motif of 4e. 5e just bores me to death. I've played through all the same scenarios a 1000 times in OD&D, Holmes Basic, 1e, 2e, etc.