First dollar coverage of many things is mandated by the ACA. It's not clear yet which things (HHS and other agencies need to first "recommend" the required services), but first dollar coverage is mandated.

http://www.healthcare.gov/law/resources/regulations/preventi...

The fact that high deductible coverage may be possible for the non-"recommended" chunk of services is a good thing, however.

(I say "may be possible" since 3 actuarial firms couldn't read the law and come to an agreement on what it says.)

Currently, every plan I've come across also covers preventive care (immunizations, cancer screenings etc.), because insurance companies realize that this saves them money in the long run. The ACA just standardizes and regulates this. This is actually in the interest of the consumer, because every plan has to have a common set of preventive care services it has to provide for free, which makes plans much easier to compare.