Since I had to log back in to reply, I checked just inserting AD2 on the normal template as well.
By inserting AD2 as a VSTi (even with all outputs shown) the default sends of each piece inside AD2 goes to master only. So unless you enable the send on pieces to either "Separate Out" or "Separate Out + Master" you will not see the levels of the individual pieces... AD2's Master buss compressor (on the kit shown above) has a fast attack with a threshold of -18dB and ratio of 5.3:1. Pretty aggressive, so the "Master" output of AD2 never clips. No biggie, so working just inside AD2 life is grand.
Some folks either want to process individual pieces within SONAR itself, or sample them for layering elsewhere. With these pieces running this hot it requires more work to achieve either of these. Mixing them within AD2 itself is no big deal (and may be why they set them this way), but they cannot simply be "routed elsewhere" without realizing how hot these are.
I have not gotten too deep into this yet, but AD2 also supports layering better than AD1, and it is easy to fire AD2 with any MIDI input. However, I do not see a method to get sounds into AD2, so I can only layer what I have bought from them (big limitation). With my current setup I can layer any sounds I choose/have access to.
The point with the OP was more wondering why the individual pieces are so hot, but unless someone used that template (or inserted AD2 and turned the individual pieces on) they would "never know."
Edit: The Audio Recorder in AD2 seems to tap into the Master out so is seeing more effect chain than an individual piece. Although this benefits layering tremendously, it is still a little "clunkier" than I am used to now.