NO..they aren't going to feel like you are wearing a cloud.
When you first get boots they should be fairly tight all over, but not to the point of 'pressure' - think of a firm handshake.
Nomensteven is spot on with how the length of the boot should feel
Walking in a boot is useless, as your foot when skiing will be stationary. Walking around in one will put pressure in spots which don't normally get pressure under skiing conditions.
The boot should feel most comfortable when you flex forward in it - this is the position your foot will be in when you are actually on a pair of skis. If you flex forward in the boot, your toes come off the end, there is still a firm hold all over the boot (The toebox area doesn't need to be TOO tight, it's good to be able to wiggle your toes) Your heel has a good hold in the heelcup (It doesn't need to be cemented in place, but any movement more than 1cm is inadvisable)
Even trying to pack out a liner at home by wearing the boots is almost a waste of time - the pressure you exert on your boots when skiing can't be replicated in your living room
Expect 3-4 days of hard skiing before your boots have got to their prime, after that the liner will have adopted to the shape of your foot and the boot will feel much more comfortable - expect the liner will pack out around 3mm or so, which is why you need to fit the boot as small as possible in the first place.
Not to mention that a boot can always be streched, and things can always be done to create more space. It's VERY difficult to shrink a boot.
So to answer your question - No. A perfect fitting ski boot won't feel the same as a perfect pair of casual shoes..
It's great to hear you are getting properly fitted.
Custom Footbeds are something I would recommend to everyone. Me, nor anyone in my shop would EVER ski without them anymore. They take pressure off your arch, keep your foot stationary and restore the foot to be in it's natural position - often making the overall fit of the boot much better, therefore much more enjoyable.
- definitely look into them.
Hope that helped somewhat