I also have a 2007 - with 75,000 miles..

I was noticing some hesitation as well and read somewhere that the vanos solenoids get gummed up - sometimes they can be cleaned and the low rev power comes back for a bit.... but since our cars aren't young anymore - do what i did and just replace them. they are super easy to replace. right on the front of the engine - two bolts and they pull right out. took me 15 minutes to do them both. oem replacements are around $200 i believe.

do a look up for the install process - i know someone did a write-up.