Would you rather they have 5-10 different abilities/states, 'Taunt', 'Threat', 'Divine Curse', 'Minor Charm', etc, with roughly similar result, or one general 'Mark', which can be described quickly, easily, and without consuming an extra page in the glossary?
Actually, that is exactly the problem with unified and generalized mechanics. Each of them works differently. You lose out of variety of effects, even if the variation is low(played some 4E myself, even helped with Mr Sinister's 4E cleric handbook back when it was still new. Didn't really feel any connection or attachment to it, but I know how it works, even if I've gone on to PF now.). That is the price for measurable and comparable mechanics. Rather than apples and oranges, they are now all types of citrus and you can compare the taste and benefits along the same track.
Taking the above effects as an example:
Taunting is a straight negative compulsion effect.
Weak taunting may reward the target when attacking the taunter.
Intermediate taunts may instead penalize them for doing anything BUT attack the taunter.
Strong taunts remove volition from the equation, they must attack the taunter, though the form is up to the attacker.
Epic taunts force them to attack what the taunter determines.
Additional penalties may apply based on the form of the taunt, but its generally speaking an appeal to emotion and instinct.
Taunting is status based, its an effect centered upon the target of the taunt.
Threatening is a control based effect. You limit the target by presenting a threat they cannot ignore.
Simple threats are the basic AoO system and readied actions, if you perform a certain action, certain other actions will be inflicted on you.
Intermediate threats are direct, if you take particular actions, you enable the threatener to perform devastating actions in response(example, moving away from a charger only means you gave them room to charge you again).
Major threats risk loss of the action entirely, in addition to the backlash price, the 3.5 version is the chain tripper or readied attacks vs spellcasting, where if you provoke and attempt to move, you are tripped, your move/spell cancels out, and then you get hit to boot.
Threats are environment based. You create an environment that is hostile to the attacker unless he does what you want. In the extreme you make an environment that is universally hostile to the attacker.
A curse meanwhile, can be presented simply as a debuff. You do not aim to direct a creature towards a particular opponent, you just outright weaken the creature in one respect, and thus steer it away from conflicts that use that area of ability. Of course, when placed upon a creature's primary means of attack, it would seek to remove the debuff effect, and as a bonus to that, the effect should be removable via some action of theirs.
A charm is pretty much everything taunting does, but inverted. You make a creature less likely to attack a particular creature and more likely to defend.
A boon caps out this lot. 3.5 bards make use of this, while they are around, they act as a force multiplier and thus draw fire, because everyone is MUCH stronger with them around. This appeals on the tactical side.
So you have these basic divisions:
Internal - The effect is status based. Debuffs are internal in nature, as are targeted buffs and damage.
External - The effect is environment based. These are usually action based, or environment altering. Things like threatened spaces, counters, altered terrain or area reshaping.
Positive - The effect encourages something to happen. It makes it easier for that thing to happen. Command is one such example, you make them do one thing, possibly to the exclusion of everything else.
Negative - The effect discourages something from happening. It makes that one thing harder to happen. Sanctuary is one example, they simply cannot do that one thing.
Reinforce - The effect makes something stronger. Almost universally applied to allies.
Weaken - The effect makes something weaker. Almost universally applied to foes.
By consolidating them all into one effect, you gain clarity, but lose depth and potential variation. An effect that counteracts one may have little justification against another, while many of them are natural or indirect controls(e.g. grease makes you unable to move pretty much anywhere, so you're stuck fighting this one guy, fog cloud makes retargeting difficult, etc)