If I understand the arguments, I think what some folks object to is the fact that if you waited one week, people would be able to get the 450 new tomestones the first week (no raid), then get another 450 after reset if you were quick to grind them, and have enough tomestones to get a chestpiece or something from the tomestone gear before stepping foot into the new savage tier, and still start on the first day. (Or you could have two accessories, instead of just one, etc.)
And I guess there's some fear that if people had access to that right out of the gate, it would 'cheapen' the world first wins because they would be done with potentially one piece of slightly better gear than would normally be available for a first-week clear? Since the tomestone gear will be ten ilevels higher than the crafted stuff.
But I honestly don't think that's a wholly reasonable concern; presumably, SquareEnix balances the fights to at least be hypothetically clearable with the minimum ilevel you can queue in with. So getting all that crafted gear on day one? That's already potentially unbalancing the fight, by that standard. Why would adding one more accessory, or replacing the accessory with one piece of left-side gear, be the final straw that broke the balance entirely?
But people don't seem to think that getting the top-tier crafted gear 'cheapens' the first week clears; I'm not sure that the potential for one piece of slightly better gear over the current hypothetical best-start gear (i.e., crafted with potentially one tomestone accessory) 'cheapens' the fights appreciably any more than using the that current best-start gear already does, by that standard.
And if it does make that much of a difference, presumably SquareEnix would balance the fights accordingly.
Meanwhile, if you feel a week one clear would be 'worth more' because it's done without benefit of better gear? Then prog and clear it with the minimum ilevel for bragging rights; that's an option right now! You don't have to get i510 crafted gear to go into the tier; you could do it with the i500 BiS of this current tier. And if they waited a week to release savage in 6.x content, that would still be an option a week later.
The only other objection I can see is if you consider the race to get an entire static outfitted with the crafted gear to also be part of that world-first race, i.e., the crafters are engaging in their own 'savage tier' to get the sets made as quickly as possible on day one. And then, yes, if you consider that part of the challenge, then delaying a week does make it easier. But no one seems to seriously consider the crafter 'first-day clears' (as it were) to be as much a race as the first-week clears are—it's not like people are eagerly tracking world-first to make a full HQ set of new fending gear, or lauding the fastest crafters on a data center ("Check out my WVR parse!")—so I think if you do consider the crafting part of the savage challenge, you may be in the minority.