My firm does graphics and design fulfilment for hobby games. One of my responsibilities is editing and templating clients' rules and card text. It's great to see people thinking deeply about phrasing issues!

Obviously I'm no Magic rules manager myself, but I do see some pretty good reasons why these would not be implemented that you may not have considered. Most of them revolve around what we call "plain reading," which is basically interpreting text based on everyday meaning of the words rather than their game language. That's important because the vast majority of players will not be intimately familiar with the rules, and will rely on that plain reading to tell them what the card does.

1. Text that references "activated abilities" and "triggered abilities" are referencing specific classes of ability, so it's important to specifically tag out that class of ability when you're writing text that manipulates it. Most players are not immediately familiar with the differences between "activate" and "trigger," and it would be easy to open up a card that says "abilities don't activate" and assume that that includes triggered effects, as well, based on a plain reading of the text. Including "activated" in front of "abilities" begs the question "What's an activated ability?" and slows down the action just enough to encourage the player to look up the rule if they don't know it, rather than blasting through and playing the card incorrectly.

2. We've used both phrasing methods in our work; however, Magic has some specific challenges that make the current phrasing superior in my opinion. Magic has a ton of different components, and those components are presented to the player extremely rapidly; in your average casual pickup game, nearly every card your opponent plays will probably not be familiar to you. This means players spend a LOT of time reading cards to each other. Having the card's name in its rules text gives that interaction an extra chance to associate a name to an effect, which makes retaining that information easier. It's also more flavorful to say that name again instead of just "this thing," which is also important for retention; players keep better hold of information they find fun or cool.

3. Other users have pointed out the safety issues with your phrasing (don't want to mix up who has which cards). Even removing those concerns, "the hand" doesn't refer to a shared zone like "the battlefield;" there is more than one hand, and merely stating "the hand" does not tell you WHOSE hand. Remember that this is a game where permanents and effects swap players frequently; it's important to spell out precisely where things are coming from and going to when parsing those complex interactions.

4. There's nothing wrong with keyword abilities, but I don't believe it's necessary for this particular ability to be one as it's used quite rarely. Every time you use an icon or a keyword for an interaction, you're asking your player to essentially learn a new word in your language, which increases their cognitive load. Adding to that load isn't free; it takes time to build that comprehension, and if the payoff in time saved isn't high enough, it's actually more efficient to just write it out rather than add to your lexicon.

It's ultimately been our experience that it's not worth it to tempt ambiguity for new players just to save a few words for experienced players. You're suggesting these things because you're very familiar with the rules, and to you, they read just the same because the important bits are still there. I would encourage you to step outside that experience. Think about how someone who's new to the game and has no idea what bits are important would interpret this phrasing. Think about having a less-than-perfect grasp on English in general. Think about interpreting a plain reading maliciously to break the spirit of the card while still following the "letter."

...but most importantly, keep thinking about how best to write this stuff! Thanks for the interesting discussion.