Except that Rakata should be compared to Battlemaster (58 v 58) while War Hero should be compared to Black Hole or Campaign (61 v 61).
I'm willing to bet there are faaar more players with full War Hero than with full Black Hole/Campaign.
That may be the case but its not a difficulty in acquiring it...My Jugg is full WH and BH geared and I got the BH gear from just running the BH Weekly and the Daily HM quest.....Was pretty easy. Dropped the mods in the tionese skin or the BM skin if you want those set bonuses and there you go..... The BH skins are so Ugly its no loss having to move the mods to another Skin for set bonuses.
Its all easy to get...Just takes time I really dont think either was faster then the other...But I feel Like I worked harder for the WH set TBH.