The article: M14 Rules Update

The gist is that the legendary rule now only applies to creatures when they are controlled by the same player, and that when a legendary creature enters the battlefield, and there is more than one copy of that creature, you get to keep one. This has also been applied to planeswalkers, for the sake of symmetry, if not common sense.
Sideboarding rules have also changed.
Indestructible is now a keyword, and the word "unblockable" has fallen out of use.
Thoughts?

The new Legendary rule is kind of weak. I know there's been a big push to make Legendary 'more fun for players', but I don't see why it's neccessary. Players already like Legendary creatures... one of the reasons why they like them is because they feel unique and special. If everyone has a copy of the latest Jace on their side of the board, it doesn't feel as special any more. We talked about Slivers, and how they could always go back, so it didn't really bother me. But you can't revert rules changes as easily. I guess we're committed to the game having less flavor on this one subject.

Though, that said, I do like how they're implementing the rules. "When you cast a Legend, and you control the same Legend, you get to keep the Legend of your choice" is a strong way to implement it. I can dig that.

'Up to 15 sideboard cards' is just logical. I don't know why they didn't change the 15 or nothing rule years ago. In theory, it's to help prevent cheating... but people shouldn't be disqualified for not wanting to build their sideboard the way they want to build their sideboard. I know they listed another reason for the change, but, to me, it didn't make sense before you bring in the game loss problem.

I'm not sure why Indestructible really needs a keyword, but sure. If it bothers people that much, that seems fine. Meanwhile, removing unblockable makes sense. Multiverse, alone, has had enough discussions over the problems with 'unblockable' when designing cards to warrant a change in the rules. It must be quintuplely problematic for Der Wizards.

The playing of lands is just them cleaning the rules, and feeling the need to explain to the public what they're doing and why. Fine by me... it's an invisible change.

Mostly seems sane cleanup. Getting rid of "I play a legend as a kill spell"... well, that's a bit of a shame, but I can see why players of the legends hated it. And in environments with huge numbers of stupidly silly legends, it either didn't matter (because there's such a small chance of a collision) or there's a couple of dominant ones (and it's just metgame pain and they ought to address the problem directly.) And yes, indestructible always was a keyword. The comp rules may disagree, but they were wrong.

So I can see it. "Build a 75 card deck and then choose up to 15 to not play each game" is nice. Going to cause some gnashing of teeth when people choose what to sideboard in their first match, though...

I am of two minds re: the legend rules. I think the original rule was better from a strictly flavor point of view, but although it did have downside issues, it also did help keep with controling the less interactive legends. I would have used the World enchantment rule: the new one always replaces the old, which does much of what they are trying to do anyway, while preserving the "legend as a defense" aspect.

the new one always replaces the old means people would hold on to them as long as possible.

clones as a way to kill legends is a stupid side effect. if geist is a problem, then hexproof is the issue, not the fact that it's legend. also, there's a whole class of normal creature and artifact removal. maybe try playing some of them once in a while, instead of relying on clunky rules loopholes.

I would have vastly preferred "new legend replaces old," no matter who controlled either. It just makes a great deal more sense to me.

Most of them sound good to me. As in, I'm not sure the new way is easier/better, but I believe them that they tried it and it does.

The status keywords is always a bit strange. It would be nice if "destroy target unblockable creature" could sensibly target something that "can't be blocked by creatures with >2 toughness and can't be blocked by creatures with <=2 toughness". But there seems to be no good way to do that, so the only way is to make things either like keywords or unlike keywords, and ignore occasional edge cases. So indestructible is a keyword. Unblockable is less like a keyword. Rules say "has defender as long as..." rather than "can't attack as long as..." etc.

I've almost never played any games where the legend rule mattered after deck building, so I don't have any strong opinion about it. I think it makes sense that it's easier to formulate a coherent strategy when you don't have to plan around your opponent having the legend. And the flavour is a little bit worse, but the previous flavour wasn't very good either.

Maybe one way to go would be that new legends oblivion ring previous legends? That way, the "summon Jace" spell works how you expect -- if you summon a grizzly bear, you get a DIFFERENT grizzly bear, but if you summon Jace, Jace stops helping your opponent and starts helping you. But he goes back to helping your opponent when he gets fed up of you. Actually, just "destroy all previous copies" would work even better from a flavour perspective, but leads to bad gameplay of everyone waiting to play their legend second.

Ironically, from a flavour perspective, clone effects are the one thing that SHOULDN'T remove a previous legend. If I summon a vesuvan doppleganger to take on Krenko's powers then I DO get a second copy of Krenko. But I suppose (1.) it would hard to be define copy effects as exceptions from the legend rule and (2.) it would remove one of the balancing mechanism for legendary creatures which are not supposed to co-exist with themselves.

The changes to indestructible and unblockable are very sensible for a variety of tiny little niggly reasons that most people won't see. I fully support them.

The legend rule changes... I'm glad Clone is no longer Hero's Demise; although hexproof generals will be even more annoying now, amuseum is right that the problem there is with hexproof or the creature, not the rule in general. I've seen lots of people complaining about the flavour of the new legend rule but I'm not that bothered.

It makes Flagstones of Trokair less good which is a pity, but it makes Kokusho the Evening Star less good which is absolutely fine.

The planeswalker uniqueness rule definitely had to go the same way as legend rule for consistency. I quite like the way it makes extra copies of the card in hand more useful than they used to be.

The flavor of the new legend/planeswalker rules is a bit off, but while the old rules made sense, it was a little forced. Mechanically the change is probably good, though I always thought that the ability for an opponent to play one to blow yours up was an intentional drawback. I like Jack's point about clones.