I have a cat, but am a dog person. The difference in intelligence is stinking. The cat can't communicate anything past meowing generically, whereas the dog can understand what I'm saying and bark on the one it wants.
When my cat wants something, she'll meow uselessly until we chance on what it is. When my dog wants something, she'll come to me and touch me with her paw, and I'll say "Food. Water. Walk." and she'll bark at the one she wants. It's amazing.
I don't doubt that dogs are smarter than cats, but dogs are far more social and are motivated to learn by that social connection. Cats can also be trained, but it's a lot more work to keep them motivated.
Cats do communicate a lot, but it's physical and sometimes subtle; eye contact, body rubbing, head butting, contextual waiting, and so on. Our cats very rarely meow unless they haven't been noticed, or, with the Norwegian, when she wants attention and she has a toy in her mouth she wants to play with - she loves playing fetch with toy mice.
While cats mostly do just meow (as much as you can say a dog mostly just barks)... my cats definitely do have variances to their meow depending on their needs or wants.
When we stayed in an RV while the house was being built, I had to put my fat boy Percy into the shower stall with the doors closed while the dogs ate otherwise he would annoy them (with headbutts) into not wanting to eat. He developed a habit of going into the stall on his own and meowing when he wanted to be fed because we always put him into the shower when food would appear for the dogs.
Even in the new house, he jumps into the tub and meows the same way when he wants to be fed.
He meows a different way when he sits at the gate or at the top of the stairs, as if for permission to interact. If you don't acknowledge him, he won't hop the babygate or come down the stairs. If you do respond, he trills a happy chirp and trots along.
He developed a whine meow where he basically is saying "I need attention now." Most recently he did it because a towel fell into his water bowl and he couldn't drink out of it.
That counts as 'food, water, walk' to me.
Oskar also has various different behaviors associated with meow types for things that get him the response that he wants. But both cats are Sphynxes and they are unusually talky... I doubt I would have gotten as much from other breeds. But they do clearly communicate what they want from you once they find a way to get that to come across.
Cat IQ depends on the cat. We had an incredibly stupid cat who liked nice but was dumb as a rock, and would mostly sit in the kitchen staring at the far wall and looking a bit dreamy. She didn't really meow at all. Or do much of anything else.
We had a couple of high IQ cats who not only knew how to communicate they were also super-social, and made it very clear to us and to visitors what they did/didn't want.
Now we have a mid-IQ cat who is quite vocal and quite good at communicating, but we have to make more of an effort than with the previous two.
When my cat wants something, she'll meow uselessly until we chance on what it is. When my dog wants something, she'll come to me and touch me with her paw, and I'll say "Food. Water. Walk." and she'll bark at the one she wants. It's amazing.