You should bear in mind that Igarashi was taking orders from Ban Dai and Toei. Ban Dai's always been the big boss in terms of Toei's franchises. What plot points did he change? The Eternal outfits? Ban Dai might've preferred to scrap them because wanted to bet on the Starlights and sell toys of them instead of another unsuccessful Sailor Mercury's doll/transformation pen/whatever. SuperS toys didn't sell well in 1995. Also, 1995/1996 period wasn't the moment to produce a Sailor V OAV because Sailor Moon was no longer a phenomenon in Japan. They could've done so in 1993/1994. In this case, Igarashi is not the person to blame.