MTGS Wikia Article about "New World Order"
Every time I read a comment about "Well if this card had card draw/trample/haste/indestructible/hexproof/life gain...", I think "You're missing the point." They're armchair developer comments that fail to take into account the card's role in the greater Limited and Standard environment. No, it may not be as good as whatever card you're comparing it to. There's a reason for that. Not every burn spell is Lightning Bolt, nor does it need to be or should be.
PSA to everyone who keeps forgetting about the Reserved List:
You're on a website dedicated to talking about MtG. You're only a few keystrokes away from finding out what cards are on the Reserved List. You're also only a few keystrokes away from finding out why some cards on the Reserved List got foil printings in FtV, as Judge promos, or whatnot, as well as why that won't happen again. Stop doing this.
Thats how its played in like 99.9% of the cases, as its the most intuitive way.
Using counters would allow the cards to still be playable if the enchantment is removed and you play another.
Just like it works with Karn.
But frankly, using the pesky counters on exiled cards is annoying , really annoying, so lots of players just dont use the counters and put the cards under karn instead (and only use the counters when it matters, because karn leaves the battlefield etc.).