In regards to the phaser thing, I'm firmly holding that the reason every Starfleet ship before phaser strips doesn't have overlapping fields of fire is significant. We don't get complaints by captains that they're being outfought, and even the Scimitar wasn't just rain-of-firing the Enterprise in the Battle of the Bassen Rift despite allegedly having something like 50 cannons and nearly 30 torpedo tubes.
There are three distinct eras. Enterprise we see lots of weapon fire from lots of small guns. Then by TOS through to TMP things are consolidated into linked phaser banks. Then you get to TNG where phaser strips can fire in all kinds of different ways, which makes sense given their design basically being something like 300 phaser emitters strapped together in a curve, each with their own power feed that can chain into each other. No reason you can't split it up. Looking forward to having to figure out a way to spreadsheet that mechanic.
The most obvious answer to this is it's a powerflow issue. The second answer is that it's doctrinal. Phasers are the scalpel of energy weapons, but they're still potent enough for military work. And the thread chose to have lower-power phasers in exchange for having to build less of them to cover more firing arc. Now as it happens this isn't especially relevant given the next choice is a refinement of the phaser banks to TOS-levels with the Warp 8 power systems. The problem is that if I throw up my hands and go 'okay you can fire as many phasers as you have on target', then phasers just become another version of torpedoes and you lose the inherent incentives to build in canon-alike ways.