Honestly, if they cut the 40 mins of ads so it wasn't nearly 4 hours for a 3 hour movie it'd be a good start.
3 hours is a long time to sit still and is complicated by the cinema insisting you buy their 1L "cup" of drink. They should bring back intermissions, gives them a reason to push the concessions stand more.
For a single uninterrupted sitting, 2 hours seems like a good length and any less than 1.5 hours isn't worth it.
