I started out as a battle mage, using heavy armor and destruction magic, switching to swords when I run out of mana, but spamming firebolt over and over is REALLY getting dull. Even spamming my sword is more fun because I get a kill animation every now and again to spice up the combat (and one-handed seems to increase significantly faster for some reason, maybe it has to do with actually getting the kill with one swing of my sword, or the fact that I always have to switch to it whenever I encounter a mage).

Anyway, I've decided to try out alteration, conjuration and/or illusion to give me some options. I intend to download a perk reassignment mod, so perk placement isn't a concern, it's mainly a question of whether or not starting these skills from mostly scratch is going to be too difficult/impossible to bring up to speed at this point.
If it's relevant, I'm a high elf, so conj is 20, illu is 25 and I've used alteration for transmuting stuff, so alt is 30 or so, whereas my primary skills are around 50 (smithing is in the 60's, I pumped it for arcane blacksmith)

One final question, using alchemy for healing potions from time to time, is it worth putting perks into?

Thank you in advance.

Why everithing in 1 build?This is going terrible wong.A mage character is suppoesd to use a mage robes to give him the most bonus.You should try only using the perks on about 6 trees or 7.
Edit:My first character was a breton with like 10 tress.He was unstoble,homever i coudln't spend my perk points on some skills....sadly.

Not too late if you use console. Yes otherwise. No respecs.

A battlemage is 1 build

Heavy armor and one handed on a mage i don't think it's going to work agaisn't some other mages.

I just dont understand this logic at all. You get 81 perks throughout the game....81. With that many perks you can pretty much do what you want with your character and not suffer at all unless your on master then it may have get a little more specific in what you choose.

Skills used so far:
One handed
Destruction
Heavy Armor
Enchanting
Smithing
Lockpicking
the random skills I use every now and again (alteration, speechcraft and alchemy, which are around 30, rarely touched.)
That... that IS 5 or 6 skills, I intend to ditch some of them too,

I have not put any perk points in alchemy. I am at level 32. I am happy with the potions I make. If I don't like them, I can sell them.

No. 1 skill I would add is block, and start using a shield.

I see,Just because we can go to level 81 i din't know it was impossible to maximize some trees.My fris build was
Block
One handed/Two handed
Heavy armor
Smithing
Speech
Destruction
Restoration
Conjuration
Lockpicking
Archery
Like 8 skills.I may have missed some....It was basiscaly the same character as you.As with racial bonus thus gaved me 75% of magical resistance and with a Shield+Spellbreaker i get like 200% of magic resistance =D

Ive not put anything into magic. Mainly sneaking one handed archery and now getting few levels of lockpicking and pickpocket

The problems with starting magic from scratch with level scaling is that it will be difficult to implement magic in battle since the enemies are scaled as well. Take illusion for example, most of the novice level powers only effect low level characters in the single digit levels. Where you are right now, you'll be facing mostly double digit level enemies, rendering the novice level powers useless. As you go up the perk tree and augment the three primary illusion spells (calm, fury, and fear), it will make it much more useful, but you'll still have catching up to do because by the time you get there, you'll be in your thirties probably and the enemies will scale respectively. Of course, you can use the higher level spell tomes (apprentice, adept, etc.), but they are costly in their mana use if you didn't invest enough magicka leveling up and you don't have the cost reduction perks, but since you have a high elf, that will help matters.

Same thing goes for conjuration... most of the lower level atronachs or weak thralls that you can summon won't be of much use to you late in the game.

Not to say this route is impossible, but it's very difficult. In fact, I would probably have gone the other way around and done mage perks first. Powerful illusion spells and conjurations can make hand to hand combat much easier to do.