I am not sold. It just a cash sink and we know cash is a problem that can be solved 2-3 months into the game.
Also in regards to space, that problem doesnt even exist. The only cramped bases I am having is the starting one (assuming no mods enabled) and thats it. Every other base once it is designed defensibly it has enough space to cram in whatever extra one needs, two or even three power generators are not going to be a hassle.
Its not going to pose a hazzard either in defense missions because you would place them away from the access lifts and hangars.
In 2012 the only purpose they served was to delay your sattelite coverage and as every gimmic in that game it was absolutely not nessessary if the game was designed as it should.