Solo SpecFollow

Of all the things you could skip, why skip Piercing Ice? It's a core talent, and a straight damage increase.

I've soloed all the old world dungeons but Scholomance (had to bring a friend for the magic-immune room).

I don't think you need arcane shielding, magic attunement, frozen core or arcane fortitude. You will need at least one point in Improved Blizzard.

You won't be taking much damage if you do things properly, and if you look at the numbers, those talents really aren't helping you very much.

Also, there's no reason at all to have precision in this kind of build. If you want the mana savings, go for frost channeling, but I recommend just moving those three points into Blizzard.

You want all the little guys to stay away from you whenever possible (boss fights where you get to go in prepared are almost never a problem). Soloing those old instances is much more like leveling: round up a group. Freeze them. Blink away. Blizzard.

I did this before the change to deep freeze, you'll be able to burn through most bosses using that now.

You'll have problems on boss fights that have mechanics that generally require more than one person, and on trash pulls gone wrong in the higher level dungeons.