Oh, the McQuarriePrise IS hideous, even moreso considering that the Ken Adam version it is built on (and built badly) at the very least looks cool & sleek.
The earlier poster asking about GR using this stuff as inspiration is looking in the right place but at the wrong person. Probert has admitted this was influential in his thinking (more the long-distance profile view where it at least looks vaguely treklike, not the painfully awkward full reveal.)
With Ken Adam as production designer at that point in his career (between THE SPY WHO LOVED ME and MOONRAKER, two high-water marks even if they aren't quite STRANGELOVE-level), you'd'v'e gotten a lot of really nice curves and molded stuff on the TITANS E. I think the exterior would have made its way back to looking less like the McQ, just in order to tie in with Adam's interiors (somebody here probably has a link to the 'giant hamster tube / French 70s era airport scenario' interior saucer he had in mind, which was a nightmare in terms of credibility but would have looked kewl anyway. The idea that you'd be able to see down into the whole of the saucer interior in one shot - which is what director Kaufman asked for specifically - is still pretty mindblowing to me.)