Fallout's TB combat is not best in class, but it is good. (Tactics TB mechanics are a notch better than FO's IMO).
The first thing to do is distance yourself from the idea that its about "I shoot you then you shoot me, then I shoot you again, ad infinitum".
Combat may literally be carved into rounds and turns, but its assumed to be taking place realtime ~sort of
.
You can consider turns for each as the perception of the same few seconds for each combatant from their perspective. AP's directly equate to time, and what a given combatant can do in a few seconds. More AP's means that they can do more in the same amount of time. Dedicated movement AP's (non-existent in FO3) mean that they can move pretty fast in those few seconds, and really get around. Turn based action divides the the time into discrete chunks and lets you examine the potentials of any choice you have very closely (and the possible choices that come of them). Combat in the game will eventually develop a kind of tension somewhat akin to "The Sword of Damocles", where the player perceives the weighted risks of taking one action instead of another. (To eat or not to eat ~should I shoot him or go heal Dogmeat
).
Fallout's original SPECIAL system has a far greater impact on your freedoms in this game. Points are finite and difficult to change permanently once you set them. A strength under 7 means you can't use heavy weapons properly, but shaving a few points from Agility to increase your strength lowers your AP's and some skills, so you can't do as much using a heavy weapon; Take it from Perception instead, and you can lift more, and do more, but are not as accurate with the weapon at range. Boost all three, and your diplomatic stats suffer, and Fallout may restrict what you can say to nods and grunts, or have merchants rob you blind with their prices.
Every interaction in FO1 is based on virtual dice ~an impartial chance tempered by your PC's skill at doing whatever you have him attempt; The Luck stat affects
all of it. High luck weights the dice slightly in your favor, low luck can do the opposite. (A curious quirk is to get the Jinxed trait, and have also the highest luck ~it makes you have average luck, but everyone else is miserable around you, with gun jams, misses and lost turns ~Don't try this one first).
Fallout's TB has double edged rules, where the enemies can run out of ammo too, and are limited to their AP's in terms of how and where they can move, and/ or use their weapons ~this is something you can figure out, and use against them. Unfortunately Fallout doesn't have a developed concept of "cover", but you can step behind a wall or close a door to avoid being targeted, (and burn enemy AP's by forcing them to open the door instead of attacking). Fallout lets you do anything in real time for free outside of combat, but mundane tasks like opening door and looting bodies costs AP's when in a fight (it relates back to the whole AP's = Time concept); It is possible to rifle your opponent's pockets when he's knocked out, and is even worth it to unload his gun while you're at it... as he won't know it when he wakes up, and it won't fire when he tries to use it (and if you stole his ammo, he can't reload it
).
Another thing is that AP's need not be spent entirely (or at all!); You can choose to do nothing ~this means that your AP's are effectively stored potential, and tells Fallout that you are on the defensive (it means that your Armor Class goes up slightly... +1 for each unspent AP. Against low level threats (IE. early in the game) this can actually help avoid injury, but its not so effective against the more powerful opponents you find later. It is the case that you might realize that your opponent has trouble hitting you with just a few more AC points ~so choosing to attack cheaply, and leaving the rest [of your AP's] unspent, might allow you to attack him every round with very little risk. Extra AC always helps.
*In FO2, with the HtH evade perk, your armor class goes up +2 per unspent AP provided you end the round unarmed (power fists don't count
) ~that can add up to a lot when in Power Armor to begin with. Most of my PC's were melee specialists for that very reason).
FO's TB combat is not perfect, and my description can't be completely accurate at all times during a fight; If taken too literally, you run into things like, "If its all happening at once, why are my NPC in front of me when I've been firing a minigun this round". Its not perfect, and won't be improved
.
*This is (at least for me), why I'm disappointed with FO3... Instead of improving it, they chose a different system entirely ~realtime, but without the foundation of the series, and it's untapped potential on modern hardware.
While I'd prefer Fallout [always] as TB, it is conceivable that FO1's combat could have been remade without turns (though not quite accurately). It could have been done with VATS-like slowed gameplay, where each combatant moved and attacked at different speeds (based on their SPECIAL stats, and perks) ~very like a "global bullet time" for all involved. (consider how Max Payne would dive to the floor, but swing his guns in five different directions to take out a group before hitting the floor). I can't vouch for if it would get boring long term, but that at least would simulate what Fallout simulated with turns.