Leeching Strikes giving 106 Stamina per light or heavy attack is nothing. With proper weaving, we will get to attack maybe 10-15 times before the 20 second cooldown expires which is barely enough to have a return investment on the ability. The chunk of stamina returned at the end of the cooldown is usually <12% of our stamina as a Stamblade, and if we cast Leeching Strikes before it is close to the end of that cooldown, it is more expensive to cost than to not have at all! (Twenty seconds for around 4.5k resources compared to the 1.5 second of Dark Deal.)
Leeching Strikes is used by Stamblades, which usually are more Melee based like all stamina classes. Melee is always a way riskier play style, which is why we need stamina for dodge rolling and blocking. Give Leeching Strikes a 2-4% return on each melee attack so that the return actually means something compared to our total resources! Add a 1 second cooldown even!