I think the team is farther along than you do, I guess. You don't ever want to stop adding talent, but the Phillies need players who can help this year as well as for the next three years, and those type of players are more easily acquired on the FA or trade market, or on minor league deals. A signing like Bourjos or even the dreaded Delmon Young is not that different from a Rule V guy, there are always those rare instances where they work out great, or at least turn into competent depth.
And Blanco had value in other ways, while Saunders had more upside than a Rule V guy (and the same floor). The whole point of a Perkins or Kelly or Stassi is that you can cycle them in and out. I guess it just doesn't bother me when a team carries that 25th veteran, whether it's So Taguchi or Michael Martinez (non-Rule V year, though he's a good person to discuss I guess. It was fine to carry a Rule V guy in that role but did it really matter either way?)
I just think this year's bench has to be better. The 5th OF should not be an afterthought (it should be Quinn if they sign a FA). The back-up 3B option is either Galvis/Crawford or they need to find someone who could legitimately step up if Franco falters, even if it's just for this season. The fungible guys who played only played because Kendrick and Nava were hurt. Signing two Rule V guys instead of two of Kendrick, Nava or Saunders wouldn't have been a good move.
That's not to say the Phillies shouldn't constantly be getting future assets too, but they'll be able to get better ones on the trade market when when it's time to move Galvis, Hernandez, a catcher, possibly even a young starter.
And in most cases even the flippable vets are going to give and get you more than the Rule V guy - their production plus their trade return.