The biggest incentive to play them is that they mill on hit with Nghathrod out but most of these only mill for two or three cards a piece, and connecting with them is not always going to be a sure thing
The best thing that WotC could do right now is to kick the Reserved List to the curb and start drafting plans toward reprinting many of the games most iconic cards
If the permanent was an Aura or an Equipment, it becomes unattached from whatever it was attached to
For just three Ink, Lilo can grant an Alien character Challenger +2 and the abilty to challenge ready characters, making it much easier to remove pesky foes from play
Ajani, Mentor of Heros 31
It's a lot like the comparison between Wound Reflection and Warlock Class: Would you rather have the immediate effect on a card that does little else, or the card that requires more mana investment but gives you other utility on the way