Indesign as a word processor

You might also consider using InCopy. If you have a full Creative Cloud subscription, you have access to InCopy. Although it often doesn't get much love, it plays well with InDesign workflows but keeps the focus for authors on the text. It also has many of InDesign's tools, including GREP, which Colin mentioned, for cleaning up text. You can even link InCopy stories to InDesign files so that authors can make edits to content, which will update in the InDesign file. That sort of workflow can work well in remote situations when the InCopy and InDesign files are kept on a cloud server like Dropbox, etc.

For most projects I see, the content was written by the author in software that they were familiar with (usually Microsoft Word) and then it is imported into InDesign by me for formatting. In my environment, the authors that I liaise with are educators, not printers or graphic designers, and InDesign can have a steep learning curve.

InDesign's import for Microsoft Word could do with an upgrade to handle graphics drawn directly in word such as wordart, floating graphics, equations etc. My preferred method is to import a word file rather than cut and paste from the word file, but I'm sure my peers here will have their own opinions. To make sure that items haven't "dropped off" the word file, I usually ask the client to submit a PDF of the same file so I can check.

Anne-Marie Concepcion has a good video on Linked-in Learning about preparing a Word file for easier import into InDesign. Biggest issue I've found is "round-tripping" where the proof goes back to the client for proofreading and edits - they either make life easy and check PDFs and annotate it using the commenting tools; or they make life suck by completely resupplying the file and asking you to make changes on top of that from a hard copy that they printed out on an earlier version.

In terms of removing space then return, some text editors (not word processors) have the ability to use "regular expressions" or InDesign's equivalent of GREP. For example, Textwrangler could solve this task by doing a find/change and looking for \p{Zs}\r and replacing with \r

(\p{Zs} is any space that isn't a tab or linebreak).

And by the way...there's not a word processor in existence that wouldn't allow you to kill those paragraph returns a lot more efficiently.