Stay at 10289 haste. It's not worth going above 10296 as it is our GCD cap with NG up. This means that most of the haste beyond that breakpoint is wasted and going for the 15k one is definitely not worth it.
Going for the 15k breakpoint is never a good idea.
If you're a hipster or something and want a different cap to go for then try 10779 as a Troll. It's a breakpoint for Meta + Berserking + Bloodlust also getting the 10681 breakpoint of Berserking + Meta. Sims at a 200-300 DPS loss from 10289. Technically with jesus level RNG it could be a DPS increase but it's not really worth going for.