I also prefer longer tanks ( at least 6 ft of length for any cichlid that reaches 10" or so), territorial fish like cichlids often will accept half a longer tank as its territory, rather than half a shorter one. You should consider all cichlids as territorial.
Most medium size cichlids need at least 4 sq ft of territory, and might accept 4ft long tank length part as there own, especially if trying to put two species per tank. This gives the less dominant species at least two ft to live with (actually 2 ft is a bit wimpy).
In short tanks, we often see a dominant pair pushing less dominant individuals into upper corners, of those 4 ft tanks, creating enough stress in the isolated cichlids, to make them susceptible to disease, or even death.
If the tank is for only one individual or a pair, a wider, yet shorter tank may be acceptable, but not for more than one species (IMO).