Disallow Stun Spore Allow Destiny Bond Allow Pain Split
Without some form of recovery outside of Lefties/sketch, Necturna will be reduced to using her most valuble move (sketch) for a simple move needed to make any defensive set. Then she will lose any coverage attack to use, or other utility move like spore that would have synergy with defensive sets/utility. Pain split largely depends on hp levels of the opponent, and so the recovery is not set at a reliable rate (low hp does make it better though). I would have preferred a 25% recovery move, but that would bias weather as a focus for Necturna.
D-Bond is a very useful utility move that pokemon such as froslass make great use of. It is very easy to stop if you know your opponent has it, and is a last ditch move anyway.
Ditto on stun spore, Necturna doesn't need to be screwing over her counters, and she's much more inclined to KO them instead of status them anyway.