I don't know what compelled me to type all this.
The St. Louis is a very good cruiser once you get the hull upgrade and it looks like a porcupine with all the guns sticking out of it. I think that one had 2 hull upgrades. Very worth it. It's a hull is very well armored in terms of what can punch through it for a citadel hit (i.e. not much). I kinda suck in DDs (destroyers) and even with the upgrade you can buy my engine and rudder constantly get knocked out. I rarely survive a match though it's hilarious when you can sneak up on the side of a BB (battleship) that the guns aren't pointing at and you know when they just panicked
The common trend with the US ships (since that's all I'm familiar with, though the Japanese ships probably follow this as well) is they all get slower to turn and reload as you go up, but the damage potential slowly increases as well. Still, going from ~8 second reloads on the Cleveland cruiser to 15 on the Pensacola is painful with fewer, even if larger, guns. You usually want to cover the BBs if the other team has carriers. Cruisers tear bombers apart most of the time.
Wait until you try your first battleship. A lot of general awareness is needed. It's like driving a dump truck on ice with a 30 second reload. Hitting an island with a DD in the area is practically guaranteed death (it happens more often that you think). You want AP shells for hitting the broadsides of cruisers for massive damage. Usually other battleships as well, but I can't citadel them for shit. This is where you learn about all or nothing armor where you can land the full volley but at a bad angle and the shells basically bounce for crappy damage! AP shells over-penetrate destroyers and usually don't do much damage unless you get a lucky hit on their ammo, so you want HE for them assuming you have the chance to shoot them when you're not dodging their torpedoes! Of course if they're in range, might as well fire away before switching your shell types if you needed to anyway. And oh god the turret turn rate on
all of them....
Then there's aircraft carriers. It's an RTS style interface if you haven't seen it yet. I finally hit the tier 6 one and it's a little less painful on the US side. I'm really not fond of the US carriers so far. Dive bombers just suck imo and I don't like them. Probably because I can't manually aim for shit with them most of the time. Their fighters usually win one on one with their Japanese counterparts especially with the aircraft upgrades on the ship and captain you can purchase at higher tiers. Torpedo bombers are where the fun is, but they're slow and get ripped up as the BB anti-aircraft guns get better at higher tiers. God forbid there is a cruiser in range too. If you're the air superiority type, you're shutting down other carriers. Once they're out of planes, you're scouting for enemy ships. It's fucking boring and doesn't bring in much XP. The strike configurations give you more 2 dive bombers, 1 torp, and no fighters... Eww. If you're facing an air opponent, you're probably going to end up a floating paperweight near the end of the match. That sucks too

. The tier 6 base one is nice because it gives you one of each, so at least you can try to torp something. It's a little rough going up the US side for carriers, but the light at the end of the tunnel if you can afford it leads to people complaining about having to fight high tier US carriers on the forums
Still despite all the good and bad, it's enjoyable and many matches have been exciting with a few that were utter bullshit

. Heh.