If, however, you wish to pretend that TOS never existed, then it clearly does not matter how you design the ship at all. If so, it's not really a redesign Star Trek challenge but, design a random space ship challenge.
This is, of course, the crux of the issue. Star Trek
influenced SF that followed it so without Trek then SF (at least in the visual sense) might have evolved differently. What other influences could have been prominent without Star Trek?
And would Star Wars even have happened as well?
Yes, it's a thought exercise, but it does illustrate that if you make one change it has rippling after effects.
The look of TOS didn't come out of nowhere. MJ reinterpreted what he knew and had seen and fashioned the TOS Enterprise
and the rest. Any creator does the same. Without MJ's influence you're assuming that everything else remains and try to draw influence from that. But the Catch 22 now is if any elements resembling MJ's designs appear in your work how can you convince others of not being influenced by him?
So, as YARN
says, you're basically trying to design something (everything) new from scratch.