The classical menu might have been adequate when the average hard drive was 200 megabytes (although I recall problems even then). But, today, when users routinely fill two or three terabyte hard drives, it's an inadequate anachronism.
Applets are the small applications that can be added to the GNOME 2 panel. In their heyday, they made the GNOME panel a place that users could customize at will.
However, at some point, the GNOME project turned away from the idea of applets. Aside from one or two exceptions like the Tomboy note applet, new applets stopped appearing in default installations. What remains is a few utilitarian applets like clocks and system monitors, and a few traditional jokes like the Fish or Eyes. In other words, long before GNOME 3 designers dismissed applets as clutter, applets were being unofficially discouraged in GNOME.
By contrast, look at the supporting ecosystem to be found in KDE's widgets, that environment's equivalent of applets. KDE widgets include tools for maintaining different profiles of key applications, quick links to social applications, a magnifier, and a virtual keyboard -- and more are being developed every week. Discouraging applets, you might say, destroyed an important part of GNOME 2's habitat.
Want to adjust how icons are displayed in GNOME 2? How the Trash operates? How your system handles external media?
In all these cases, you don't go to the System menu in the panel or open the right-click menu on the desktop. Instead, you open the Nautilus file manager and select Edit -> Preferences. Not only does this arrangement tie you to a brain-dead file manager, but it could hardly be more unintuitive if the designers were trying to be unhelpful.
Exactly why the arrangement made sense to developers in the early years of the millennium has never been clear to me. However, mercifully, most other desktop environments have long since left this setup in its grave.
Most installations of GNOME 2 come with at least two default icons: Computer and Home. These defaults are not removable from their right-click menus, which, for most users, means they can't be deleted at all.
That wouldn't be so bad, except that neither is needed. The Computer icon duplicates part of the contents of the Places menu, while the Home icon is unnecessary because the file browser opens in your Home directory anyway.
Both icons could be replaced by the file browser in Applications -> System Tool, which is a modified version of Nautilus for administration -- to say nothing of the only version worth using in the first place.
Many people complain about the design assumptions in GNOME 3. However, those assumptions first sprang up in GNOME 2.