Not exactly true. Yes, you have to deal with ill effects, but once you randomly generate an age without blindness or nausea, you are more or less set. Every non-Void Age I've created has a Mystcraft Library in it within a couple hundred meters of where you spawn. As long as you can see normally (thus nausea and blindness are no-goes) you can find it. Slow effect is a problem, as is Weakness, but a Modular Power Suit with Sprint Boost means you can run away from stuff.
Those libraries have roughly 8 to 10 pages each,if you catch the chest hidden behind the bookshelves. 15 Ages in, I have all the necessary pages for a stable Age, minus Normal Sun. And I have the Charge page to add stability to make up for it. I have a mining age now that just has Slowness instability, and you get under cover that goes away.
BTW, destroy the book linking an Age, and I believe you can the go to your save and delete the DIM folder associated with it safely. I think. Back up your save first, mind.
Edit: As a bonus, non-Mushroom Island Ages generally have quite a few Thaumcraft altars. If you are willing to do a little traveling, you can get mad lootz. I have 4 portal guns now.