Recently, I tried to find an explanation for the phaser bank issue.
My thinking so far is that there are two energy distribution networks in the ship. A low-power network for simple stuff like computer consoles, doors, light and so on, and a high-power network for phasers, shield generators, the computer core and the like.
Both networks would not transport highly energetic plasma (warp plasma) but only relatively low-powered plasma, because it's only a transport medium for electricity and it wouldn't be safe enough to circulate warp plasma through the whole ship.
In TOS, the phaser banks would siphon some plasma off the high power network and use the electical energy (also taken from the network, not the plasma siphoned off of it) to charge the plasma to a warp plasma level. This is then fired through the phaser emitter crystals and part of the plasma particles are converted to nadions (the plasma charges the crystal and starts some kind of exotic reaction in it which then gives off the nadions or modifies the plasma around it).
By TMP, the plasma conduits are then safe enough to carry highly energetic warp plasma through the ships high-power network (which also still carries electricity), enabling the phasers to directly fire this plasma without the need to charge it anymore.
And by TWOK, they added the charging function back to the phasers as a backup, if warp power fails.