Even working with computers kitted out with around 2GB of RAM and a 2GHz multi-core CPU, there’s no reason why a lightweight Linux desktop environment can’t offer a fairly full feature set. It’s never going to greatly affect memory and CPU usage to offer conveniences such as a pleasant-looking theme and a searchable application launcher.
As for the layout, it’s sometimes interesting to see a modern approach, but quite often – if you’re outfitting an older model computer – you might be getting it ready for someone who isn’t