I'd say it depends on what you want from the game. I'd say there's plenty of kinky and exciting scenes with Ian as well, if you follow Cindy (nothing beats that excitement of mutual seduction with her), Alison and Emma paths. I guess beating the shit out of Robert on more equal terms can be exciting, too, if that's what you're after.
Well, the way I see it, the routes with Cindy, Alison and that girl with glasses are all the most basic romantic paths (I haven't played anything with Emma because I don't like her look). Just different representations of the same type of content. Sure, some people enjoy stuff like that, I mean, many people buy romantic novels after all. But I think it is not the most enjoyable kind of content for the patrons of Eva Kiss, many fo whom became her patrons because they had enjoyed GGGB, which has very little of such content and is more focused on corruption, cheating, incest etc.
I'm quite sure Eva's supporters would enjoy Ian's part more if it had, let's say some BDSM content with Holly, or maybe NTR stuff with Alisson, or maybe if Ian's mom would appear (since many for some reason love this stuff). Just examples. Romantic stories are fine, but not so many fans of porno games enjoy them.