I'm a little late, but actually this started fairly recently, in the mid-1990s. Nicole Bobek (1995 U.S. National Champion and World Bronze Medallist) had a spectacular spiral and most of the rest of the U.S. ladies worked hard to keep up, and now it's become a feature of the national skating "style". Before that it wasn't so prominent. But personally I don't like most of the extreme spiral postitions because it requires a fairly ugly displacement of the hip (i.e., leg to the side instead of to the back).
As for the question about twizzles, the free leg position (as opposed to the skating leg-- the one with the foot on the ice) is optional. As long as it's controlled, you're generally okay, unless it's just an ugly position. Twizzles are scored right now, basically, on number of revolutions and entry edges (or, really, changing entry edges and directions in a twizzle sequence-- the edges themselves aren't given much credit, as if the ISU believes each of the 8 twizzles is equally difficult, which is certainly not the case). Obviously the turn needs to be steady, balance held, unison kept (into, during, and out of the twizzle), etc. In my opinion twizzles are given way too much attention in the new scoring system-- ice dance is not about being able to do an 8 revolution twizzle (as I saw one jr. level dancer working on the other day). I've heard the ISU is thinking about restructuring the twizzle requirements, but nothing will be definite until after Congress (in June, I think).