With all the construction, it's pretty easy to half-day it.
This simply is not a true statement. It may be a half day park for some because what it offers does not hold their interest, but the reality is that with all of the shows and characters, it's virtually impossible to do HS in a full day, let alone a half one.
The vast majority of the attractions are still open. The area that is under construction came from attractions that required a large amount of space, but not a large amount of time (Backlot Tour, Lights-Motor-Action, Streets of America, etc.).
Yes, it takes longer to 'do it all' in Epcot. But, that does not make HS a half-day park if you want to do it all.