The early to mid 2000's / late 90's was when hip hop was really peaking on the charts while there were still enough sensible hip hop songs being released, so the 2000 time period will probably always be a huge marker when it comes to classic hip hop.
Also, Will Smith kept it real. When it comes to decent rhymes and formulating a flow, he was an expert of those times. He is part of what "real" hip hop was all about, and also made a lot of classics, so it would make sense to play Will Smith on a classic hip hop station.
I'm pretty sure they play NBK on Power. Maybe not during certain times, but I'm sure it does play every now and then at some point. I'd think NBK is more regional. It would work in Phoenix and parts of L.A. as a classic, but maybe not in New Hampshire or Delaware or something like that.
They'll probably dig more into the roots as mix shows and possibly other specialty shows arise. For right now, just the basics, which is typical in most traditional formats today.
What would be interesting is to see The Beat in 5 to 6 years, when many of the dumb hits from 2006-2008 were released became old school! I wonder how they'll sort through and decide which dumb hits (soulja boy, laffy taffy, ay bay bay...etc) and many of the other pointless hip hop hits should or shouldn't be featured on the playlist, then it will become even more interesting as today's "hip hop" or HIT music becomes old school, especially with the big changes taking place in music now! A lot of what is passing for hip hop today just because it was done by hip hop artists, I would never consider to really be hip hop. It's more pop, and "hits" is a more accurate description unless your station is one of the few staying true to only the hip hop hits of today (for example, Power 106 LA now sounds more like a "hits & hip hop", while hot 107.9 in Atlanta still sounds more like "where hip hop lives").