I added a red dot and supressor-height sights to my G17.3 a few weeks back. I have fired just over 700 rnds with this setup. I'm still getting acclimated overall. But one thing is clear: shooting with a dot definitely does improve my shooting with irons.

Comparing viewing the constant movement & wobbling of the dot to the sight picture with irons makes irons seem absolutely dead still---and this seems to build the confidence level that I can place shots exactly where I want them, and easily. Sure, I still have to grip correctly and work trigger carefully, but these tasks seem to fall in line behind that seemingly rock steady sight picture. My overall shooting experience & results with dot and with irons are improving significantly.