The conclusion does indeed require a return to the thesis, but a good conclusion requires more. Remember that a proper conclusion is not merely a summary. Otherwise, it would be called a summary, not a conclusion. Rather, a conclusion ought to draw some conclusion about the topic of your paper. Hopefully, you'll always have an answer to that question beyond the aforementioned necessity of completing an assignment.
Conclusive language sounds like a conclusion, and often needs no awkward signal word.
If you're truly endeavoring to provide a signficance to your paper, you may be providing all the transition you need. The point is, be aware of shifting from one part of the essay to another, and do it smoothly. Return to the thesis rather than re-stating the thesis. Both you and your reader should now have a greater breadth of knowledge of your topic after experiencing your paper. So reflect greater knowledge in re-packaging your thesis for the final time in the paper.