IMO, I wouldn't do the trade b/c Hibbert is a solid big man that will likely do substantially better next season (he is only 26). Furthermore, West and Hibbert are the only legitimate bigmen for the Pacers. Additionally, Lopez's production is likely gonna stay the same or deteriorate b/c of Unibrow, whom you already have. On the other hand, having a first pick next season is tempting, especially if you have someone in mind (I haven't looked at the rookies yet).
So, unless you have a rookie in mind that you now will help your team, I wouldn't do the trade. Besides, Lopez is 2 years younger and will likely "break-out" in 2 seasons, IMO.