I'm playing a sort of jack-of-all trades character for my first run through, with points in sneak, archery, light armor, one-handed, destruction, restoration, and conjuration. I've been hesitant to sink any points into either of the crafting trees, because my playstyle is so versatile I haven't decided which will benefit me the most yet.

I pick almost every ingredient I come across, eat any that I have no knowledge of (my character is level 29 now and it is very rare that i find an ingredient I haven't already eaten), and make a [censored]-ton of potions. Likewise, I gather every pelt/ingot I find and do every possible smithing action I can without perks, and I enchant as much as possible. The funny thing is, I'd say I spend more overall time crafting potions than I do smithing and enchanting put together...but my smithing is almost at 50 and my enchanting is somewhere just past that, while my alchemy is still a lowly 30. Why is this? I put the most time into it, and I've made hundreds of potions, but my level is still extremely low and almost all of my potions are still pretty much useless. So useless that they would not benefit from a 50% bonus, much less a 25% one. Which is odd because I can upgrade weapons and armor to Superior quality, and if I have a decent soul gem handy I can make a useful enchantment.

So...why is my alchemy taking so long to level, and what level (if any) does it actually become viable? Is it ever viable without perk points?

The rate at which alchemy grows is dependant on the value of the created potions - regenerate [stat] potions tend to be the best to grind on for fast levelling of the stat.

Even maxed out alchemy is pretty weak in terms of raw bonuses for end-game play without boosting alchemy with enchanted gear; but don't forget you can buy +alchemy magical gear from shops or find it in dungeons if you're lucky. It's highly advisable you keep your eyes open for it if you eschew enchanting to create your own alchemy gear with.

The actual potions though are great; with proper enchanting gear it's possible to create poisons of around 200 direct damage, or 250-300 damage over time, +40-60% damage potions, +100-160% magical damage (Which synergises with enchanted weapons as well as spells)

I have once perk on alchemy and skill around 70, my potions are useful. Not the greatest but many are useful and some of the mixed affect potions are down right awesome.

Also check this link

http://keke.itarium.ch/uploads/alchemy/

Will allow you to out in what ingredients you have and it will tell you they most valuable potions you can make, and more value means more xp.