Are all those wires just a gimmick?
No, the wires are not a gimmick. Most modular synthesizers do not have normalized connections between the different modules. You needed a wire to get the sound of the oscillator to the filter. You needed a wire to get the envelope voltage from the envelope generator to the filter and the amp. You needed a wire to get the control voltage from the keyboard to the oscillator. Etc.
Basically, you need a crap ton of wires. (Or patch cords if you want to use the technical term.)
Some modular synths included some sort of normalization scheme. The
eMu modular synthesizers (very expensive but very good) included the ability to set up the normal signal flow from module to module behind the scenes as you added modules. The front panel jacks overrode those signal paths. So for most sounds you wouldn't need any wires. Other semi-modular synths were generally set up with normalized paths but could be overridden. (The
Arp 2600 was such a synth.) It was called semi-modular because it had patch points available that you could use with external equipment or to override the normalized signal paths, but generally used by itself. Examples of modern semi-modular synths are the
Moog Mother-32 or the
Pittsburg Lifeforms SV-1.
So, no, the wires aren't a gimmick. However, as happyrat1 said, there is a gimmick involved, in that the vast majority of the sounds played by Keith Emerson probably didn't require using the big modular Moog. In fact, from my vague memories of watching him play, he very seldom used it on stage at all. I think it was primarily used with the ribbon controller. He relied on the Minimoog for most of his synth work. (Until polyphonic synths became usable, the vast majority of his playing was on organ and piano, not synth.)
From talking to someone about the big modular Moog behind him, one reason it was so big was so that he could have a couple of sounds set up on it without having to repatch sounds live during the performance. If you had three sounds you'd use that night with two oscillators per sound, that meant six oscillator modules. Etc. But it did look good, didn't it.
[Edit] He also used the big modular synth for the sound between side one and side two of Brain Salad Surgery, in the middle of Karn Evil 9, and the sound at the end of Karn Evil 9. I don't think Minimoogs included a sequencer or sample and holds, which were essential for those sounds. For that you'd need a modular synth. [End edit.]
Recreating a MiniMoog on a big modular synth would require (off the top of my head), a keyboard that produces a control voltage, gate, & trigger; three oscillator modules, two envelope generators, a voltage controlled filter, a voltage controller amplifier, a white noise generator, and a ring modulator. And wires to connect them all. Heavy and expensive. (But more flexible than the MiniMoog itself.)
