Problems:
The whole concept of the guide in my opinion. Banner of command is a fairly weak item and does not deserve a whole build around it. The problem is Ali has a slow push speed, no escape route and is SO much more useful with the rest of his team. With those items the lane will only push slightly faster than if no-one was there. Leave back dooring to shen, TF, nidalee and yi.

Scaling mana regen seals. You are getting about 0.5 mana per five seconds to start with and it never becomes a noticeable amount. Try armour seals.
Glyphs of armour. Glyphs are not good at giving armour. Use MR glyphs instead.
You do not need a chalice on ali.
Why would you get runic bulwark if you aren't going to be anywhere near your team? Not worth the stats it gives minions.
Extremely odd masteries.

your runes are ummim not sure about them but at all its realy nice way to play him you should try it with taric it works great also

your runes are wrong, for an explanation.

Alistar is an AP offtank, a support tank or a tank.

in your guide you made a support tank.

as a support tank you need as much utility as you can and get them to cd off at faster rate. i would suggest maxing Q or W then E as last. you only need the E to activate trample as it's heal is not enough to be useful in a fight (you'll run out of mana quickly). your heal to your allies would only be around 110 at the cost of 80 mana. that would not really be wise because you would be lacking damage and much more valuable CC (1.5sec knock and a knockback) which is the core of alistar.

your runes makes no sense because as an ap tank you need armor and not mana regen. if you are so insecure about your mana regen then buy a mana manipulator early game then 2 more faerie charm (which is not advisable for ali) on your next back for your chalice.

lot's to improve here, everywhere. hopefully i have helped. no vote.

-1 das ist alles

Questionable itemization, questionable masteries, questionable runes and questionable skill sequence.

I don't understand this quote "I don't aim to have the best build, I am to be a choice"-Len. I just... don't. Also what is with you and Greater Seal of Scaling Mana Regeneration runes? Even if those were viable it would be better to get Greater Seal of Armor and Greater Glyph of Magic Penetration. 4.5 armor and 10.8 mana regeneration or 9 armor and 9 mana regeneration? Do you have problems with just smashing your face on the keyboard and not having mana even with a Chalice of Harmony? This is just wrong. It isn't hard to manage mana and even if it was you have a Chalice of Harmony.