The original X-Com was worse in this respect. While the conventional equipment varied quite a bit, but at the end game everyone was carrying a Heavy Plasma, because it was strictly superior to anything but a Blaster Launcher.
While Double Tap is nice, In The Zone is a fantastic skill in the right situations. It’s a big deal when you take down 3 enemies in one turn, and it’s amazing if you’re taking down 5. It works every turn, where Double Tap only works every other turn, so even when you’re killing 2 enemies at a time it can be higher firepower. Even when you’ve only got one target, it lets you shoot and then move, which the Sniper can’t normally do.
The main drawback of In the Zone is that the target must be exposed. Flying critters don’t take cover, period, and a rocket attack can both clear away cover and weaken the targets enough to make one-shot kills likely.
If you don’t like suppression and Mayhem, it’s because you’re not using them correctly. Suppression may not do damage, but it can save lives. With Mayhem it does automatic, cannot miss area effect damage. “Can’t miss” is huge in this game.
That’s definitely a “you’re doing it wrong” issue, because psi attacks are in fact quite powerful. At a guess, it’s because you were using soldiers with relatively weak Will. Being psychic does not increase your Will. Rather, you want to test the soldiers who have high Will first, because those are the guys who are going to be useful if they turn out to have Psi.
Will is random - all Rookies start with 40 Will, and gain 2-6 points before Iron Will per rank, and 4-12 afterward. This means you really must start a new squad after buying Iron Will, because your Colonels are only going to have 64 Will on average, and 76 at most, which is very weak. You want 90+ Will on a good Psi soldier.
Mindfray is 5 points of damage, which isn’t a lot in the late game, but you can usually get a 100% hit on the target regardless of cover. The 25% to-hit penalty can be quite significant, as you may have noticed if any of your guys get Mindfrayed. It also weakens Will - it’s possible to mind control an Ethereal, but it requires several Mindfrays to soften them up first.
Psi Inspiration is +30 Will, area effect. It’s not a defensive ability, it’s an offensive one. You boost your psionic comrades to really high Will levels so they can take down more resistant targets.
Panic is powerful, but dangerous. Used right, it’s a crowd-control ability that lets you completely shut down a hostile for 2 turns. The problem is that they may panic-fire, so you only want to use it on targets somewhat behind the enemy line, so they’ll shoot at other aliens instead of you.
Mind Control is awesome. Take out an enemy, and use them to kill the others? What’s not to like? The main drawback is that while you can make them throw away grenades, you can’t get them to throw away their weapon, so they’re dangerous on the turn they revert. At least you can put them out in an exposed area that last turn.
TK field is “everyone around me is in High Cover.” The main drawback is that it works on enemies who close enough to be included in the field, so it works best for longer range firefights. What’s more, Will doesn’t matter, so even low-Will psi soldiers can use this.
The last level does rather suck. While I think the base assault mission is also repetitive when you play the game a second time, it’s better than the highly scripted last level.
That’s why you like rockets so much - you’re playing on Normal, where rockets can reasonably one-shot enemies. The game changes on Classic. Normal is good to learn the game, but you have to play much more tactically on Classic, because anything less than High Cover is an invitation to die.
