This is an idea that I've been thinking off for a while... you can easily make a healer, illusionist, conjurer or destruction mage, but alteration focus? It sounds so stupid but I wanted to try it.
First thing I need is a better name than Alterer or Alterationist.
Using a shield and the lord stone, you can get armor rating without disabling the mage armor perk, allowing for an armor rating as high as 375 without any smithed armor. I'm also supplementing the build with non-spells that do thematically fit in alteration. Think of the staff of magnus, the slow time shout, tower stone in the aetherial crown...
To keep the build viable, I'm also going low skill to prevent leveling too fast. Alteration and block will be used, but not sword-and-board. I can't decide between destruction and enchanting, or both. Staves are great and can be used to not level destruction, but that leaves the issue of soul gems (I'd have to soul trap or barter a lot, adding conjuration and speech into the mix) and I can't get the augmentation perks. Actually using destruction, and going shieldmage means I can't dedicate to health upgrades for tanking.
A sword could easily limit the build to just 3 skills, which seems ideal to me, but I'm thinking it might be boring and not too different from a build using heavy armor instead of alteration.
Why not use Scrolls instead of Staves? They're a little less frequent in their use, but Scrolls are nearly as rare as apples in Skyrim, and the Black Books can be abused later on to get massive amounts of scrolls (they reset after a certain amount of time...which I can't remember) that and some of the more basic spells aren't exactly the most expensive (Things like Fireball). I'd still pick up Speech to make it easier, but I think a character could be set up using only Speech, Alteration and Block.
By the way have you considered the use of the Serpent Stone, the Tower Stone doesn't actually work in the AC (I know it sucks, but because it isn't a Power, more a passive) so the Serpent is a good Alteration based replacement. It can pack a bit of a punch and the Paralysis is a powerful enough spell to add at a lower level. I know it might seem silly but I always liked throwing a punch at the same time as using the Stone, it kind of looks like you've lobbed acid at someone
What about Ash Rune, Ash Shell and Paralyze? (I assume your not taking it to level 100), they can become incredibly powerful with a little bit of investment. Simply use Stability (which I assume you'd pick up anyway), Dual Casting (though this might make it cost too much) and then consider picking up some Shalidor's Insights (Alteration) and Paralyze at least can become a really useful tool, dunno about the Ash Spells, never tested them.
I like what your working with so far MFD and I'll keep track of it (or try to at least), though I will say you should probably change the title (at least temporarily) to something like WiP Character Build: Alteration Mage...It doesn't need to stick but the Workshop Rules would dictate you need a proper title
Hm, Alteration, block, speech, staves and scrolls. A Scholar maybe?
I like the Alterer-but ill see if I can think of anything better.
The temple priest robes would look dope for this build-maybe spell breaker, even though it looks awful.
Yah, that could work, I was mostly just going for the color theme, bright flowy robes.
You might want to consider Vampirism, and utilize the Vampiric Grip (offensive telekinesis) as your only weapon. Without Destruction, you'll be vulnerable to Animunculi, Dragons, Dragon Priests, and a few other creatures. However, there should be a price to pay for the power of Vampiric Grip. You are an Alternation Mage after all... why not use the ultimate expression of your power?
You can also combine Vampirism with Necromage, Agent of Mara, Breton racial bonus, and Magic Resistance from the Alteration school to become nearly immune to magic.