JD has energy leech which does not make the mobs aggro and recharges reactors so the reactor recharge is really the same for both shield and energy leech. Giving the JD shield leech and the DPS gain would not hurt or unbalance the warrior classes because like you said over time the TW and PW do more damage where as the JE is not a damage dealing class. Yet my JE with 2 lvl 4 beams can out DPS my JD with 4 lvl 5 beams. Every time I use shield leech the mobs aggro on my JE. This should not happen. If the JE had energy leech he would still be providing the reactor recharge that shield leech does but would not pull aggro. This is more in line with the JEs DPS, hull size, skill set and group bonus.
Akela