I disagree. In regards to the Leif Ericson, I didn't say anyone "had it in mind", I only suggested certain features of the concept art
by Jefferies -most notably the engines- bear more than a passing resemblance to those on the Defiant. This suggests that those responsible for these features on the Defiant as we know it, were familiar with Jefferies concept art and/or the model kit, and were, at least subliminally, influenced by either one or both. If so, it would not be the first, or last, time those in the Star Trek art dept. took inspiration from among Jefferies earlier concept art.