Discounted/Incentive-driven mass subscription gifting
An incentive to gift more subs would be to "throw in" additional gift subscriptions when purchasing bulk subscriptions.
5 gift subs gifts 5 subs for $24.95
10 gift subs gifts 12 subs for $49.90
20 gifts subs gifts 25 subs for $99.80
50 gift subs gifts 60 subs for $249.50
and so on. I'm thinking a 20% bonus at each tier, or the bonus could even tier up based on the amount. I believe it would create incentive to gift even more subs as the gifter would be given credit for the gifted amount, rather than the base amount.
In theory, you'll get more LARGER gift amounts, and that also increases the chance subs will be gifted to someone who will choose to continue said subscription as well.
I believe this would be a win for everyone.