Choosing to take the easier (logistic, non game-related) path is the result of a preference for doing so.
The WotLK 10/25 was fundamentally flawed. It formed that way because of historical reasons, so I don't blame Blizzard for that model. But with hindsight, moving back to that model would be silly.
Personally I don't think your view represents the majority of the WoW playerbase. I believe the 15 man option was conceived in the interests of the 25 man community and represents the interests of those raiding 25 man, or who are stuck in 10 mans because they cannot find a 25 man.
It is, IMO a pretty horrible compromise because it guarantees that you will please neither the 10 man nor the 25 man community (although the 25 man community will feel better than it would being forced into 10 man).
Nay, the best option is to keep 10 and 25 man pretty similar to what they are now. Add a few small incentives to 25 man to counter for the logistics, sure. But if insufficient people are prepared to go to the effort of doing 25 man, then clearly most of them are not as passionate about the format as they claim and the 25 man format does not deserve to survive. That being said, as long as there is still some interest in 25 man raiding, I support Blizzard keeping it alive.