The issue is a maxed out tachyon beam might just might do more shield damage to a player with normal stats in insulators than their passive shield regen. The sci ship would take of more shields in that time if they had instead used their weapons and diverted the power into weps.
Atm the best shield stripping ability a sci ship has is the vesta's cannons/tric mines.
The major issue I see with tachyon beam is that the shield damage is to all facings. The reality is it is far more efficient to drain one facing, two at most, and then start working on the hull. By spreading the damage out you are taking down shields that are on facings away from the damage and therefore not getting the benefit of them being down. Now if you could take that same shield damage and focus it on one facing then you'd have an ability worth using.
Tachyon beam 3 and tractor beam (with doff) used on an escort with tactical team won't drain the shield facing you but you will see the other 3 facings go down to red and barely anything there. Another escort can swoop in and murder the unsuspecting foe.
Oh wait attack pattern omega removes all holds, gives a speed and defense buff and with an engine battery and evasive that escort is healing half the map away...
As for PvE you can get some decent shield stripping using Tachyon beam 3, tractor beam, charged particle burst 3 and maxed flow caps but an escort would bring down shield facings on multiple enemies faster.
It's a shame they can't have a skill multiplier/divider for sci skills between PvE and PvP which will buff them to be useful in PvE but nerf them so they don't dominate everything in PvP