Sure it might be even better with curtain wall. I personally don't have an issue with the mullions, but either way it has mullions and the glass it has, and it looks good.
Why waste time wishing for something that's not going to be happen. Atleast this is something that's nice. Regardless of whether it could be better. It could be worse.
Nice vantage point! ^ . INDX has been looking a lot chunkier than I had imagined as per many of the recent photos, maybe perhaps because a large portion of it is covered from most angles. But in that shot, you get more of an appreciation for its height (also picturing Sapphire tower rising in the same spot topping out near the antennas of FCP )