Overall, we enjoyed Disneyland: there are many interesting locations where you can take great photos. The only downside is the very long lines for the rides. You spend half your time, if not more, just waiting in line.
We had two days, and in that time, it's quite realistic to visit all the locations and see all the shows without Premier Access. However, to do this, it's best to arrive very early, because there can be long lines even to get in, and then leave late in the evening.
If you're only visiting for one day and are willing to pay extra, it might make sense to get Premier Access for the most popular rides.