Herp derp let's just rambo into the enemy team to catch the ashe 2000 units away so i can ult her and get 2 ticks off!! Ya know they can like kill me? I'm not just saying stuns. The point im trying to make is you need to figure out HOW to pick apart their biggest threat. Im not telling you to ult the tank or some ****. Also if you get behind in lane/ganked/etc you can lose level, gold, therefore losing items and skill levels which means less damage, so yes in some very bad cases you can't 1v1 an ashe. That was just a figure anyway. It can be anyone that has heals/regen cause casters have these things called cooldowns. Intelligent targeting is ironic because if the enemy team is intelligent they'll be targeting you as soon as you so much as sneeze on their carry. So that means find a good position. Behind your team, behind terrain, THEN pick a good target. You're worth nothing if you just die immediatly.

If you are going to play your skills and with your team so badly as to not be able to 1v1 ANY ashe, then you need more practice with malz. If you are going to talk about them canceling your ult with a stun, (the reason you grab BV) you should try ulting when it is beneficial to your team, not just cuz it is off cd. Malzahar's ult has 1 of 2 purposes. To either disable the largest threat in a team fight, or to kill of a burst character without much risk. If you throw Call of the Void and then immediately combo/ult then you needn't worry about a stun. You MUST have intelligent targets otherwise Item build doesn't mean much.

1. What I should have said is he's no longer godlike omg op mode, my bad.
2. I don't run any mana regen runes, so the rings are helpful. But mainly it's the ap and health that make them worthwhile. I did mean to say 2-3 in the guide, that was a typo. You could also ask any higher level player if it's ok/good to stack up to 3, and they'll say yes.
3.Zhonya's gives you a lot of extra ap, armor never hurts, the passive is pretty damn good. Trust me on malz you're gonna get focused literally as soon as you ult. The invuln helps for between cooldowns when you are being chased etc... Let's say you blow your full combo on an ashe and it gets her to... 200 hp. She has bloodthirster so she can just kill you with the lifesteal while your spells are on cd. So pop your zhonyas. Who cares if they run? You still lived. That's just a 1v1 situation, it's also helpful between cooldowns in team fights if you're getting focused. Just because you have good positioning doesn't mean the enemy annie/sion/brand can't flash in and kill you. Will of the Anicients isn't really a defensive item, it's an ap item that has an aoe buff. The buff goes a long way, trust me. Why wouldn't you buy banshee's on Malz? That's like saying, "Hey guys, I'm ulting your teemo but you can just stun me npnp." With void staff and sorc boots you shouldn't have problems with magic pen, and void staff>abysall if the enemy is smart and gets mr.
4. Yeah that was a bug, idk what happened, will fix now.

Good
flash makes for great combo placement
speed makes for great harass
Large amount of magic pen hits harder than straight Ap
Will of the Ancients is great for survivability and giving ap (helps your team too)
ignite goes well with malz's full combo

Bad:
First: ryze was not nerfed into the ground (not the reason I down voted, but just correcting you)
Second: Doran's ring is cost efficient, but 3 is overdoing it and ends up wasting your cash. You don't need that much mana regen because if you use your Malefic Visions correctly, it gives you back plenty of mana. If you want Doran's Ring, one is quite sufficient.
Third: Your overall item choice is largely defensive ( Banshee's Veil, Will of the Ancients, and Zhonya's Hourglass) and yet in your strategy you talk about staying in the back of the fight and casting spells from a safe distance. Switch out banshees for Abyssal Mask; you get MR and more Ap/mpen.
Hourglass is very situational on malzahar, because he doesn't have abilities which can benefit from it (such as karthus's defile or fiddle's ult)

also, you have 2 of every section (fix it up and make it more presentable)
sorry, but -1