Well Suited - WORKFLOWS! To a SharePoint Developer, workflows are like a hammer to a carpenter. If there is a business process that needs automation, the first thing I look to is what are we automating? What/where is the data? How can we minimize the number of keystrokes by end-users to get from the start to finish? The answer to all of these is "build a workflow". With the introduction of "Call HTTP Web Service" action, you can now access data anywhere in a site collection and consume it in any site, on any list, for any form. SharePoint Designer Workflows makes the SharePoint world go round. Less Appropriate - Building SharePoint Pages I have attempted to use SharePoint Designer to build custom pages, but it just is the worst tool to use. There are many other tools to use to develop customized pages. The techniques of designing custom page layouts, CSS files to populate in pages, JavaScript Snippets for pages have changed so much over the years, and SharePoint Designer did not change with them. In fact, it is my opinion the 2013 version made it 100 times more difficult than the 2010 Version.
SharePoint Designer offers more granularity of customizing a workflow that is more sophisticated solution that can effectively delegate tasks to responsible parties and reflects status updates of task status.
SharePoint Designer allows SharePoint professionals the ability to customize a SharePoint site with HTML5, CSS3, and JavaScript that can be integrated in .ASPX pages.
SharePoint Designer offers form customization where Office products such as Word, Excel or PowerPoint cannot meet specific government requirements and or expectations.
Navigation between sub-sites and beyond the entry point is not seamless. I find it difficult to get to the root of a directory structure if I have not started there.
Would love to be able to do WYSIWYG in some form. I have only used it for a year but I have not found anything fancy to do.
I would like to be able to work in a development site and easily move to the production site.
Support is good from Microsoft. They are quite responsive when we raise a ticket but SP Designer support will be ended by Microsoft in the near future as they have got new techs like PowerApps and Flow to achieve the same functionality SP Designer does and even more than that.
In order to simplify our internal workflows, we have installed additionnal tool for our SharePoint platforms : Nintex Workflow and forms. Compared to Nintex, SharePoint Designer is very far away. I am only talking here for 2 main features of SharePoint Designer : - Workflows - Forms But for these 2 features, Nintex is way above SharePoint Designer
With workflows alone we have had a positive ROI because it gives us increased functionality and value with a smaller amount of development time needed.
The testing of workflows or pages is more structured and we have less base cases than a ground-up customized development solution.
Occasionally, we will have a negative impact on our ROI based on the work-arounds needed to make SharePoint Designer work for a specific project, but overall there has been more positive impacts than negative.