Looks like G Loomis is re-releasing the IMX line as the "IMX Pro" line of rods. I noticed that IMXs and their specialty lineup are all on sale on TW, I wonder if the IMX Pro is replacing both of those lines of rods to simplify their offerings. That would make sense...
So now we've got the E6X at $200, IMX Pro at $300, GLX at $400, and NRX at $500. These were released in 2015, 2017, 2016, and 2010 respectively.
It sounds to me like the NRX is the next line of rods to get an overhaul.