B and C are not necessarily an argument against A, as it depends upon implementation. It all hinges upon loyalty, and not activity days, as the main factor that should decide upon whether or not someone should be rewarded a WP or not.
While loyalty is hard to judge on an objective basis and measurement, one 'could' use activity days for it, by assuming that if one did indeed play for so long, that one must've done at least something. Maybe get a panel and ask for 3, maybe 5 non-alts of higher age to vouch for your activity or loyalty and get a very amount of activity days as a requirement, such as.. 500? 700?
One can (I haven't done the math, because it's not exact science, but rather a guesstimation) reasonably and arguably attest that over such a high amount and with people of higher age vouching for you, that you are loyal and that you should be rewarded with a wp for it.
As for B and C, I can understand that you may see these as arguments against A, but you haven't exactly argued as to why these are so bad in the first place. I can see how they could be bad, but if the implementation is right and it gives an impulse to increased loyalty and activity, and not just an impulse to log in for a minute a day to get the activity days, then why would B and C be so bad?
You speak as if alt abuse would be the biggest and most severe problem, right at its implementation. But that doesn't have to be so, not if the implementation is done correctly.
Also, you speak about the fact that this is favoring the veterans, and I agree, however, once more, if only A is your intention, then why not implement it in such a way that it favors veterans for the right reason, which will also stimulate newbies to become such loyal veterans.
I think I convinced myself into changing my own vote from 1 wp per year, into 1 wp per 500+ days, maybe more, with the added restriction of proven loyalty.