To what extent should the translation respect the grammar?

[MarcoP]

all is not rosy in word pattern land

I totally agree and I believe that catastrophizing is perfectly justified. Some of the word patterns in Voynichese are quite different from what one sees in written natural languages, e.g.:

• high frequency of reduplication (e.g. daiin.daiin);
  
• even higher frequency of partial reduplication (e.g. f103r.4 ychedy.qokedy.okedy.qokeey.okey);
  
• very frequent character sequences that occur across words (e.g. edy_qo, see You are not allowed to view links. Register or Login to view.);
  
• many words "prefer" to appear in different positions inside lines (also You are not allowed to view links. Register or Login to view.).
  

But the fact that making sense of these patterns is horribly difficult does not imply that they can simply be ignored. If the question is "should a translator care about grammar?", I believe that the answer must be "yes". Grammar is not an optional part of language: if we conclude that there is no grammar underlying Voynichese (however buried under a very clever or maybe very clumsy writing system), the implication is that there is nothing to translate.