Yes, I agree. I like to see a mix. I do like seeing clubs come up, stay up and do relatively well but it's also good to see clubs who haven't been in the top flight before (or for many many years) come up, even if it isn't for long. If nothing else, it helps those clubs financially if they use the money wisely.
The pointless ones are those who are constantly up and down between the Premier League and Championship, never actually getting any better.
Generally speaking I want as many "proper" clubs - older, bigger clubs - as possible, because it means there are fewer fixtures I've got zero interest in watching. There's just something way more interesting about Villa vs Leeds than Reading vs Bournemouth.
But Brentford would've definitely been a novelty.