Rather than tell you exactly what is wrong or right with Fallout: Tactics right away, I first want to demonstrate something that is absolutely essential to understand this game.

Fallout: Tactics' gameplay exists in a bizarro world where the bugs are so entwined into the game, that they practically become game mechanics.
What? How is that possible? Simple, it is impossible to avoid the exploits and bugs that exist in this game, you cannot help using bugs in this game to your benefit, simply because they do not allow you to not use them, that is how ubiquitous they are.

Strange?

It is. Here are some examples.

- The burst mechanics are unbelievably bonked, there are single shot weapons, then there are burst weapons, whereas the previous Fallout games treated burst weapons as essentially volleys of several shots, burst weapons in this game function more like shotguns, they just spread out in a cone behind whatever you're aiming at. This means that they quite literally almost ALWAYS hit whatever's behind your target. Have a 0% hit chance on that Super Mutant over there? No problem, your Vindicator Minigun will liquify anything behind him, leaving him unscathed, but hey, collateral damage is still damage.
If you use any burst weapons in the game, this will happen, you cannot avoid it, and burst weapons are not optional to have a good time here, since they're so utterly broken as far as damage is concerned.
The bad part? If that Super Mutant levels his gun at you, he'll liquify your entire team and leave just one lone turd standing.
Another side benefit, don't bother using your Traps skill to clear minefields, just aim in front of a mine and watch your burstfire usher forth a cacophany of explosions.

- Stat altering perks, traits, actions, etc. can become permanent. Entering your APC while prone? If you exit it somewhere, for whatever reason, your skills will be permanently boosted because God willed it, I guess. Pick the Night Person trait? Yeah, the negative parts of it basically never trigger again after your first mission, and the benefits are permanent, you can then go on to Mutate that trait and still keep the stats. There are several more instances of this, it's so common that you might not even notice when it happens.

- Throwables phase through matter. If your character's throwing skill is good enough, usually around 100% (which is a fairly low value easy to obtain early in the game), they can pretty much throw grenades through walls, windows, doors, any kind of obstacle you can imagine. It's easy to see what's screwing up here, characters with bad throwing skills are clumsy, and thus their grenades could hit cover in front of an enemy, rendering the attack ineffective. Characters with good throwing skills would be able to avoid whiffing, abstracted, the intent makes perfect sense.
Yet for whatever reason, 14 East never decided to make walls de-facto impenetrable objects, an absolutely insane oversight, since now you can chuck grenades into buildings, gibbing anything inside without retalation, it is a completely viable (albeit excruciatingly slow) strategy to take nothing but throwing characters and be able to beat most missions with zero effort, provided you can obtain the necessary grenades, of course.
I actually have this inane bug to thank for me being able to beat the game at all, since apparently some degenerate slob thought it was a good idea to add enemies whose corpses in death become impassible obstacles, blocking me from an objective I needed to destroy, but the Lord was merciful that day, and I smashed a grenade through the narrow atoms of a wall.

- You can make mechanical turrets overdose. Just apply some injectable Psycho or smear Afterburner Gum all over their innards and watch the helpful tool tip tell you that this non-thinking creature has just become addicted to a psychoactive substance. You can them make the turret overdose and die, presumably choking to death on the absurdity.

- The exit grids can become completely inoperable for arbitrary reasons, you better hope you have a save decently earlier, because otherwise your poor knob has been cooked. This game killing bug can trigger as sensitively as me simply leaving the last bunker before the last mission, realizing I needed some more items from the Quartermaster, returning, then realizing I couldn't leave because I wasn't supposed to come back. Thank God I had an earlier save. All I had to do was tediously kill the same robots I had already killed for another 3 hours before I could end my misery by ending the game.

And so on. The list is nigh endless. This game is busted, its chunks fly at you in an endless parade of total ineptitude.
What about the rest of the game? It's buggy yeah, but is it fun?
For the first ten hours, Fallout: Tactics requires a reasonable amount of thought and planning, fights are close, popping off rounds at a distance, sneaking up on raiders, mowing them down with burstfire, perching yourself in high towers, lockpicking doors to find alternate paths. The level design is open, and allows for multiple approaches.

Then you reach the early midgame, and as soon as that first Super Mutant drops your first Big Gun, it goes down hill, at this point Fallout: Tactics doesn't require even a modicum of thought, you can take one single character, dope him up on Psycho, and run through entire missions just blowing things away with a SAW.
And it's almost as if the developers realized this fact, and rather than balance the game, they just gave up, the relatively interesting Beast Lords and Super Mutants give way to dull, tedious robots that are nothing but HP sponges in gigantic levels that take forever to beat without offering the same variety or options as the earlier missions. The promise of new and interesting guns doesn't exist either, the energy weapons are nothing but various Small Guns or Big Guns redressed to shoot green and red crap.

Lump that in with the absolutely abysmal, braindamaged AI, and you have a game that turns into a completely unchallenging slog, it's extremely easy, but it takes way too much damn time to scour these massive levels, killing huge amounts of enemies that are too stupid to even walk within adequate range to be able to hit you. Super Mutants will spend an eternity spewing rounds at you with a 0% hit chance while you snipe them between the eyes for ten minutes with your worthless Sharpshooter.
The first mission with Super Mutants even has an area that is obviously supposed to be extremely difficult to clear out, and the game recommends you avoid it, but since the enemies will never bother getting close enough to actually hit you, you can send your mostly useless Sharpshooters to take potshots for 30 minutes, slowly clearing the place out while giving you massive XP as your non-worthless mooks run around mopping up the rest of the level.

The problems in this game are endless. Most of the Recruits are emphatically useless, and seemingly gain completely random perks as they sit in the Recruit pool, forming a competent team in this game is entirely centered around taking the Recruits with the least completely nonsensical SPECIAL stats, and then hammering them into shape over the course of several levels into something they clearly weren't even intended to be. Your best Energy Weapons user isn't going to be one of the intended Energy Weapons recruits, your best Medic is probably going to be your PC, since all the Medics are absolute human refuse, and your Pilot is going to be nobody, because Piloting sucks, the vehicles are pointless besides being glorified loot vessels and you'll probably just take him and let him stand at the starting point of each level soaking up XP so you can slam points into his Gambling skill to rob merchants since Gambling in this game is as hideously broken as everything else.

There's nothing here but an absolute mess of a game, from every possible standpoint.
So honestly, just skip Tactics.