Looks unpleasant.
1. Cannot breed two Pokemon with the same Defense DV AND same Special DV (or +/- 8). Makes it tough to slowly improve a Pokemon.
3. Takes the DVs of the opposite gender parent. Assuming that: Grabs Defense 100% of the time and Special 50% of the time. Randomizes Attack and Speed.
4. Offers no in-game way of viewing DVs. Might figure it out with a calculator. Probably means leveling the Pokemon a bit.
Also discovered gender is determined by Attack DVs. Means only male Pokemon (or Pokemon of a female-only species) can have maximum DVs in Attack.
Hm. What are the odds of breeding a perfect DV Pokemon?
Assume two non-Ditto Pokemon with an even gender ratio. Has a female parent with maximum Defense and Special DVs. Makes no difference what the male Pokemon is.
Male egg: 1/2 chance
Defense: 1/1 chance
Special: 1/2 chance
Attack: 1/8 chance (8 - 15 DV range because of being male)
Speed: 1/16 chance
(1/2) * 1 * (1/2) * (1/8) * (1/16) = 1 / 512, or about a 0.2% chance.