Sister Zeynab, I mean the atmosphere is different perhaps mainly because social class distinctions have deepened. Qasbahs are generally viewed as middle-class accommodations nowadays. Moreover, some basic architecture of modern qasbahs have also altered. Though the labyrinth of alleys do still exist, some qasbahs have done away with the incline of wide steps .... I guess to facilitate the entrance of small vehicles like motor bikes. Then again, you can see electrical wires and telephone lines criss-crossing over the roofs of homes. Many structures in new qasbahs are built in apartment style, three or four storeys high. All such innovations clash with the archaic medieval style.
Check the images below for clearer understanding.
Here's a modern Algerian qasbah. The architectural layout is the same yet you can discern it's not quite a medieval dwelling, particularly if you're acquainted with the standard depictions of the Islamic middle class society of this part of North Africa (as shown in Sister Heba's post).
Here's another one. As you can see, the steps are made a bit differently .. in pairs of two with a longer walking space between each pair.
This one is very much on modern lines. These apartment-style homes have a very high plinth and stairs going right up from the lowest floor to the highest in crisscross pattern. These floors also have balconies or open hallways used for spreading laundry.
This is a nice qasba with that slight old-time touch.
In this qasbah they have done away with the wide stairs altogether.
Another nice one I like with a quaint whiff despite the modernity.
And see this, the caption below explains it all. Very interesting.
Movie was filmed in Algeria. As explained in the original post, this is the reason it was so difficult for the French occupiers to handle the revolutionaries. As you can see in the image, they are ordering the people to step out but are too afraid to walk inside the qasba themselves.