It is worth going for and in S15 gear is pretty easy to get there. But you need to fix your reforging, gemming and enchants i.e. intellect on claok instead of crit. Putting yellow gems everywhere is a mistake. Use a combination of Quick, Reckless and Shattered/Sensei gems to grab as many useful socket bonuses as you can. Even after this you'll be able to get above 14873. Change the default stat weights because they are useless: mastery should be really low, crit higher and then hit optimise.
Just by putting your char into AMR I ended up with around 30% crit, 35% mastery, slight above hit cap, 14873 haste cap, but also gained 1,45% PvP Power, 639 Intellect and 700 Spell Power. So you really don't need to sacrifice anything.
All top Spriests are using the DP3 breakpoint(14.8k). Enchant your bracers and go crit instead of mastery--crit is what nets you kills. Also consider switching from Insanity to FDCL and Power Infusion to DI. Aren't many top ranked Spriests(if any) running Insanity these days, and DI is too good to pass up.