What I mean is, there's no reason a person who uses two handed swords can't begin to sneak and use bows to make things a little easier. So the advice is perfectly valid.
Didn't say it wasn't. Some people play using all the skills and doing everything. But most don't. Unless it is specified, and it wasn't, we should be safe in assuming that the OP is playing a specialized class. Giving advice to do everything is not wrong. It just might not fit the playstyle of the person you are advising. Still, I guess they are free take it, just as you are free to give it.
I find that spreading points and perks too thin is a bad way to go. You will be stronger and the game will in turn be easier if one focuses on a few skills to advance and invest perks in.
And...saying that Skyrim doesn't have classes is not entirely accurate.