As much as we hear your need, this is not currently on our road map. We will revisit it eventually.
We don’t plan on adding progress indicator as we feel it would only become misleading because estimation are really hard to make due to technical limitations.sarwar.rana commented
Overall the product is really good and so is customer service but progress bar/estimated time is definitely needed. I can understand it could be hard but at least start from somewhere basic. I can't believe that it was raised in 2016 and now we are in end of 2018.
oh, it would be good idea if someone from Sharegate can actually respond on this?