I would say based on what we've seen with the class skills, the game is shifting focus on abilities that continue the flow of combat. With enfeebles as they were in terms of silence, para and such they in a sense have a stagnative feeling in the fact they don't do any damage to the monster so if you're a player trying to get an enfeeble/debuff to stick countless time, you are slowing down the pace of combat because you are focusing on enfeebling rather then inputting damage.

I believe enfeeblers will come back but as seen with some of the magic abilities, the enfeebles will do damage as well as have a chance to enfeeble so that the flow of combat is always moving forward.

For quick examples here are the following:
-∟CNJ Mag. 9 O Target AoE Deals wind damage to all enemies within range of the target. Chance to dispel an effect.Combo: CNJ Magic 8, Bonus: Increased accuracy against target.
-CNJ Mag. 10 Deals earth damage to the target. Chance to reduce evasion against earth magic.
-THM Mag. 4 O Self AoE Deals ice damage to all enemies within range. Chance to inflict Bind.
-　∟THM Mag. 9 O Deals lightning damage to target. Chance to inflict Stun.Combo: THM Magic 8, Bonus: Increased damage and reduced cast time when Stun fails to trigger.
BLM Mag. 3 O Self AoE Deals fire damage to all enemies within range. Chance to inflict DoT effect.

As it stands now the only enfeeble type that doesn't do dmg, which it shouldn't is sleep since that acts more like a pacing tool to control pace of battle. As for the other enfeebles though I wouldn't be surprised if we see them come back in the form of dmg+enfeeble effects.