It depends:
1) Have you EVER been there before?
If not .. then there is easily still a full day's of attractions and shows there (you probably won't be able to do them all just on the timing of some of the shows)
2) Do you have little kids?
If so .. there is a lot of cool kids attractions (Disney Junior) and Meet/Greets there now
3) Do you (or your family) like Star Wars
The park has a ton of non-ride Star Wars attractions - shows, fireworks, a "parade", Meet and Greets, stores, etc.
4) Do you have interest in seeing the night shows?
If so .. then a full day is fine there.
5) Were you planning on getting hoppers otherwise?
Getting hoppers JUST for DHS is probably not worth it in my opinion.
The only downside is that because of the severe lack of QUEUE attractions (rides), and the small "walking" space, the crowds and lines for those four rides will probably be long (but on the plus side, can Fast Pass three of them, so really no downside).
On my last trip to DHS I purposely spent a half day there, only because we had just been there 18 months earlier and my kids aren't big enough to ride two of the rides. The Star Wars stuff was new, so we spent time seeing/doing that and then left at lunch. But I already had hoppers banked into my tickets, so it wasn't any extra cost.