Choice with consequence was the design goal.
A choice with consequences that's so bad as to never be taken is a non-choice and therefore manifestly not the design goal.
Yes, I would say that the design goal was to create stickiness for the Fighters to allow them to act in the Defender role. Rather than going with some sort of "If he attacks a monster, that monster can't disengage" they gave the DM's some options. He can shift away at the risk of taking a hit, and he can attack someone else at the risk of taking a hit and a -2 penalty. Or if the enemy was hit by a ranged attack and wasn't adjacent to the Fighter, it would just take the -2 to attacks against other targets. Even the 1 CC attack has some reason behind it.
..x
.F.
..C
x=Marked Enemy
F=Fighter
C=Cleric
In the above scenario the monster has several choices. He can continue attacking the Fighter, attempt to shift or move away from the Fighter, or shift towards the Cleric and attack him. Now, if he shifts away from the Fighter he'll take a CC attack. If he tries moving away, it will be an AoO and if the Fighter hits it would stop his movement entirely...so that's a much worse choice (not to mention all the bonuses to AoO's that the Fighter might have).
However, shifting to the Cleric would provoke a CC attack, but actually attacking the Cleric would not since CC's are capped at one per round. What this means is that if x is actually some big baddy like Irontooth, he can shift past the fighter, take the CC attack and then wail on the Cleric free of charge. Well, there's that -2 to hit, but for a big baddy going against a softer target like the Cleric it shouldn't be too much of a problem.
So as you can see, this allows the Fighter to be sticky, but also allows the DM to make tactical decisions about when it's worth it to risk ignoring the mark and provoking attacks from the Fighter. Personally, especially if that Cleric was already bloodied, I would take it. You have about a 50% that the Fighter will hit on that CC, and 1 in 20 chance that it will crit. Plus, it's a basic attack, so it's just the average of the weapon damage plus ability mod. For my Fighter at level 1, when we fought Irontooth, that would've been an average of about 9.5 damage, and 14 damage on the crit. That's not a lot of damage at all.
Now, this is just talking about the Fighter though...my group also has a Paladin! He can mark you, give you that same -2 to hit, and actually cause some damage if you ignore it. He and I also try to create walls out in front of the squishies. So against us, CC's and AoO's are very unattractive. At least in the dungeon environment we're in now, trying to get around us could lead to several AoO's. So we make a pretty effective wall.
If a party had just one Fighter though, that's a different story. Now you have someone who is more limited in who he can mark, especially if sticks to more single target powers (I have Dragon Breath, which I use to mass mark and minion kill). Additionally, he's only limited to one CC attack a round, and he can't fall back and attack enemies who get past him, which is important.
If you rush our line we have several options. The Paladin can peel off and start using his marks on the enemies that get past, meaning they would be taking damage for going after the squishies. Plus, he'd be wailing on them. Or I can peel off and go back an attack the enemies that rushed past. We'd also most likely be able to get easy combat advantage against them, which means they would fall pretty quick unless it was a big baddy.
When you only have 1 Defender though, he can't peel off and go attack enemies that get past him, he has to hold the line. Perhaps part of the reason that the DM in Verision's game provokes so many AoO's per round is because there's only one Defender. Every guy that gets past their Defender is one more guy that the Defender can no longer engage. He needs to hold the line otherwise
all fo the bad guys will get through and swarm his allies.