I've tried it, I like it but I do not find it addicting (or maybe it's just me). It will attract new people if advertised properly, referring to players with zero Ragnarok knowledge. I haven't checked the cash shop but I am assuming that it's going to be a very cash extensive game.
tl;dr It's good but as an old guy who doesn't enjoy mobile games and who's used to the Ragnarok PC Game, I don't find it addictive. So people with the same perspective like mine will still end up playing RO1 after few months in the mobile game.