Well, a cat will crave the outdoors, and obviously if a cat has never experienced the outdoors it won't know what its missing so it's not cruel per say - but it is best for its health and well being to have a little bit of outdoors time. The thing is here is that all cats are different. You see these huge pampered fat cats that love cuddles on the sofa, then you see those slim, healthy cats that hunt and play outside. Rescue (its best to rescue rather than to buy) a kitten from a shelter - after a month of indoor play time and cuddles let him/her explore the garden (with supervision) for an hour, next day a little longer and gradually introduce him/her to their surroundings. that way they have experienced the comforts of indoors and the thrills of outdoors and will have a balanced lifestyle, where they stay very close to the house outside and ENJOY being inside. This is what we have done with our cats and they are extremely friendly, love attention and are quite 'dog like', as you said, but also go outside to go to the toilette and explore a little They each go outside for maybe a couple hours a day when they want to, but love our company and follow us aroun
True, if your cat goes out sometimes, you may have to invest in worming pills and flea spray twice a year or so. But its worth it, when your cat is bright eyed and bushy tailed, right?
Another thing you could do is get two cats. It is true that cats like their alone time, but they also value company and when you're at work and the cat is at home, he will not be alone and bored.
One more thing; An indoor cat will stink out the flat with his littler box. Seriously, its not pleasant having to smell it when you get home then cleaning it up. The cat will probably find a corner that he prefers, too, and poo there instead. It's a nasty business looking round the house for the mysterious farty smell and finding a fresh one behind your wardrobe.
So the verdict is you should let you cat out, even if its only for an hours supervised 'play time' everyday. They will be so much healthier and happier!
TIP: Moggies (normal, mixed breed cats) tend to be much healthier and long lived than pedigree cats. These pedigrees are often sickly or have some defect as the centuries of over breeding has led to incest and weakened immune systems.
Hand raised several kittens from birth. Nine cats.