NO. Riot has already addressed the issue of her stun, specifically the topic of having her stacks fall off one at a time, but this answer also applies to having them fall off completely after not using it:
"This is a neat idea, but it has a few issues:
Most other champions with their Ultimates ready already put out the pressure that they could use it at any time
This would make roaming or hiding in ambush with Annie a matter of spamming abilities constantly unless the decay time was trivial and it would just get reset in the lane pressure situation."
http://boards.na.leagueoflegends.com/en/c/developer-corner/3IXxdZwi-mid-year-mage-updates-annie-direction?show=rundown
Plus, if an Annie is holding her stun forever, then she's not able to farm, and that's not playing right. Most Annie's don't do that until team fight phase when she needs to hold it until the right time to let it loose, which is when the enemy groups up and fights. Also, she's a burst mage man, her damage is supposed to be high. Nothing will change that unless Riot decides to change her numbers around but that won't happen most likely.