True CPU usage will be higher, but will it make a noteworthy difference? For 16KB vs 128KB, i think the added CPU overhead is made up for by acceleration of files in the 32-128KB range (in wich lots of the common OS IO requests fall).
I'm curious One Hertz, where do you have this info on write-combining and write-amplification suffering from 16KB stripe?
It's possible i've misunderstood the inner workings of the Intel controller, with clean block/page pools, and pools of dirty/semi-dirty waiting for cleaning.
As far as i understand, the controller will always write to the pool of free pages, and will not make much of a difference wich of the blocks the free pages belong to. The LBA that gets written will trigger the old LBA to be listed as dirty and to be cleaned at a later time, so if 1 LBA or 8 gets listed as dirty on the same time shouldn't matter.
Also, when it comes to 4KB write vs 32KB or 128KB, if you test ATTO or IOmeter, 4KB sequential @ QD 8 gets performance pretty simelar to 32KB @ QD 1 (wich is what a 32KB file will be written as respectivly on a 4KB and 32KB stripe). Each Intel SSD supports up to QD 32 nativly, so a 4KB stripe would limit you to 4KB sequential @ QD 32 bandwidth from each drive, wich is close to full sequential bandwidth. I don't have excact numbers, but it would be interresting to do a benching session on it. Unfortunately i don't have Intels myself, or i would do it.

I do not mind being proved wrong, as long as i learn something. If you have something i should read, pleese link it