The only real difference between your PoW approach and our giveaway is that yours requires people to waste money and resources on needless PoW computations and ours doesn't.
There are more differences than that:
1) Proof of work allows anyone to participate in the production of XRPs
2) The resources used to create the proof of work are not wasted, they contribute to the decentralization of the distribution
3) There is already a large user base of SHA-256 miners (the Bitcoin miners), the amount of "wasted" resources used to mine XRPs is negligible since people are already mining Bitcoins
4) Any additional mining participants that the demand for mined XRPs brings in can also contribute to increasing the Bitcoin hash rate, which is not a waste of resources
The distasteful aspect of Ripple is that the creators gave themselves all 100 billion currency units. I greatly prefer "wasted money and resources" going towards mining than this alternative. But I don't even consider it wasted resources. That's YOUR opinion, and you're hardly unbiased. How much effort really went in to thinking about ways of distributing the XRPs that don't involve starting with a hoard of the entire stash of them?
Developers MUST BE RELIEVED of the responsibility of XRP distribution AS SOON AS POSSIBLE!
If you mean using PoW to distribute a currency: Sure, that works. But it's arbitrary, unfair, and wasteful. It makes perfect sense for bitcoin because it's needed to secure the blockchain. It's functionally equivalent to auctioning off the currency as the people willing to invest the most in obtaining it wind up with it...
No it is not unfair nor is it wasteful. You said it yourself that XRPs are needed to prevent transaction spam and that they have to have some marginal value for this to work (or else they could be cheaply obtained by spammers). You are right that XRP mining would not be "securing the blockchain" but instead it would be "making spam expensive."
You claim that the mining of XRP leads to wasted energy and resources but
wasting energy and resources is a requirement of the Ripple system to prevent spam! If in the future the acquisition of XRPs does not require an expenditure of energy or resources, then it cannot function to prevent spam.
What's the difference if someone works at Burger King flipping burgers and then pays OpenCoin $5 to get XRPs for opening an account (after XRPs are no longer given away for free), versus a miner who works at Burger King to pay for the electricity and equipment depreciation to merge mine Bitcoin and Ripple for some millibitcents and drops per day?
There is no difference...
except that with a proof of work system the creators do not gain unjust control over the entire money supply.