You'd slacken it by around a degree (assuming same volume tyres f&r) and lower the BB by roughly half an inch
If DH riding is your thing rather than pedalling up technical climbs it might be a good option for you. If you're the type of rider who gets lots of pedal strikes it's probably not.
The slacker HA and lower BB will make the bike more stable (in corners and at high speed) and the slacker seatangle can be sorted really easily by simply moving your saddlerails forwards in the seat clamp. Bear in mind reach will be shortened very slightly and seated distance to bars more so.