The devs certainly seem excited about the news ("We love working on Payday 2 and look forward taking care of our game for two more years, making new free updates, paid DLCs and awesome campaigns together with the community") but I decided to ask Alice as she's someone here who actually plays it.
"I'm curious to see how they plan to satisfy grizzled veterans without alienating newcomers," was the reply. "I started playing a few months ago but already am overwhelmed by DLC bits I know I'm missing, and am put off rather than enticed. But Overkill seem to be getting better at striking a balance between free and paid additions."
I just checked and there are 27 bits of DLC listed as available, from Christmas soundtracks to diamond store heists. Some are free updates while others, like the Dragan character pack are a few quid.