It was my understanding that the
Comprehensive Rules would change a number of cards, making some weaker and others stronger. Okay, fine. Wonderful, in fact. I looked forward to the coming of 6th Edition, gleefully anticipating all kinds of exciting new card interactions.
I even thought making interrupts into instants was a grand idea (Counterspell fan here).
Nevertheless, there were some cards that unexpectedly became broken. All of the wanna-be Black Lotus cards were among them. The new rules made them as good as the original, and totally defeated their purpose.
Waylay is a more complicated issue. I nearly (literally) fell out of my chair when I read that Waylay could be played during th opponent's end step, allowing the tokens to attack the next turn. Cool, and brutal with Crusade.
I openly and vehemently opposed errata for Waylay, since it didn't seem all that broken to me (particularly, in retrospect, considering what R&D foisted upon us during the Artifact Cycle). Later, I felt that an errata might be warranted, not because the card had suddenly become so powerful (I loved it, myself) but because it was "out of flavor" for white to have what amounted to a remarkably versatile Ball Lightning.
I was sorely disappointed when the errata came out, citing something like "not the card's intended use." So what? If they had seen Trix coming, using Illusions of Grandeur for what couldn't have possibly been its intended use, I doubt they would have even batted an eyelid at Waylay.
(Apologies to
Dune Echo, by the way, for debating when he asked us not to, but I really do have an on-topic point.
)
My point is this:
Errata to maintain a card's functionality is fine. Lion's Eye Diamond and its cousins were
meant to be crappy versions of Black Lotus. Without errata, they might as well have just been Black Lotus, and errata was the only option, other than banning.
Errata to make a card behave the way you want it to (and I'm still baffled as to why they "fixed" flagbearers with errata that will rarely make any difference) is not okay. Waylay was suddenly a great card, and fixing it was unnecessary (and the final errata was just stupid).
Finally, I'd like to offer up a whole class of cards that changed under the
Comprehensive Rules. Almost none of them received errata. The artifacts. I think that every single artifact where the shutoff-when-tapped ability being lost fundamentally changed the card's strategy should have gotten errata, or none of them should have. Two got it right away (Winter Orb and Howling Mine, if I recall correctly) but others (notably Static Orb, until much later) did not.
In summary, errata to fix something that is genuinely broken due to rules change or oversight is okay. Errata to "fix" something that isn't broken, but simply works in an unexpected way, is not.
In my opinion.