Is the improvements to the new LA heads, enough to not reproduce the W-2 head anymore

Time and technology made the W2s less cost effective, and in time, not very effective. It's simple economics: if people buy, they'll keep up support. Fact is in the late 70s & 80s W2s were "the head". But you had to buy the heads, the valvetrain, the headers, and the intake to get them to run on your engine. In the 90s it was about weight and better port layout - the W5s were "the ticket" as far as Mp product. But the execution was so poor on the base castings taht they immediately got a bad rap that continues to now. Time has added new port design, chamber design, flow theory, and priority on weight (mostly for the circle/dirt track guys) added many new options. The W2s became the equivilent of the 392 hemis. Great engines that can make power - but technologically out of date and unable to make the power a top-of-the-line race wedge or hemi can do now.
MP is phasing out all wedge based stuff. Big and small. The production line Hemi stuff is just taht good, and cheaper to re-tag and sell. They are trying to keep in step with their market. The old stuff isn't their market any more. Hasn't been since the late 90s when the aftermarket really jumped in to Mopar.