I'll start off by saying that people aren't coming across these overpowered builds in natural, roleplaying fashion. They use console commands to experiment, post up their results then hundreds of people copy their formula and complain about how easy the game is.
My main point is that clunky hybrids aren't going to be balanced. The ability to experiment is what makes this game great, but experimentation will always result in different degrees of viability. If you want what feels like a ideally balanced experience you would be best served to pick a finite role, though.
Well then I must be in some strange category of people, as I determined the synergy of smithing/alchemy/enchanting on my own. I started out with smithing, just having fun making steel armour to wear, then dwarven/orcish/ebony/daedric in a rather fluid manner.
I dabbled in enchanting, as I realized that while enchanted items were nice, the prospect of dual enchanting (something my character learned by apparently starin up at stars) seemed so tempting. Finding fortify smithing items only proved that enchanting could allow for a stronger smithing ability.
Upon finding a fortify smithing potion I learned that crafting could be fortified via alchemy. This caused me to practice alchemy until I could make capable potions. And then I realized I could iterate through this to create stronger gear.
This actually did occur in a fluid and "natural" manner. About the only "cheating" I did was determine that there (fortunately) was no fortify enchanting enchant, or fortify alchemy ingredient.
It can occur in a fluid, RP sense. To forcibly say "My character doesn't even consider enchanting" though is just silly. Its an option thats readily available. Its right there. Theres even a quest to try it out. Yes, you may be a warrior, but you can indeed cast soul trap with little to no issue, and enchanting an item takes so little effort.
My point is, once again, how the heck do you so narrowly define these "roles" and get away with calling it good roleplaying? Roleplaying almost inherently means coming to an understanding of how the artifical world that surrounds you works, and working within the constraints of that artificial world. If enchanting is so easy for the Dovakhin, then why not do it?