Why visit 2 theme parks instead of the same theme park twice?

1.- To experience different rides.
2.- Yes
3.- in Disney California Adventure, we used our phone to play an interactive game with the big Mickey ferris wheel before the World of Color show.

I think it is a given that people will visit theme parks more if there is a new ride or experience. For example the wizarding world of harry potter. Made universal actually rival disney in terms of emersove experiences and increased visitor numbers by a lot, so much so that it will open in hollywood this year.
Personally I tend to visit theme parks more when there is something new. I will most likely visit alton towers this year for the new galactica ride is will will start to use VR headsets to make a whole new experience.
My family and I when we went to florida in 2014 used the new disney experice and my magic tech to really help with booking fast passes and most of all being able to quickly book and manage restaurant timings. This then enabled us to change what we wanted to do during the different days that we were there and it was really easy to use on the app. This made us visit the disney parks more than the others because of this tech.

There are pros and cons to visiting a new theme park vs. returning to one you've visited before. Some of the pros are that a new park is a new experience and that you may find it is even better than what you've visited before, but the possible downside is that it might not meet your expectations and therefore you might not enjoy your visit. When returning to a park you've previously visited, you have a good idea of what you're getting, but if you visit the same park too many times it can get stale (this is often a problem with local parks if there isn't a major addition).

As for responses to the specific questions you're asking...

If you have visited two different theme parks I would like to know why you chose to visit a different theme park instead of returning to the first one you visited?

When traveling, I generally prefer to try somewhere new instead of returning to a previously visited location. For theme parks, I keep a list of all the parks I'd like to visit but haven't gotten to yet, and on every trip I make an effort to include at least one new park from that list. While I enjoy all of my local parks and visit them regularly, I've found other parks that I like just as much (or possibly more) than my local parks, and a couple of them are places I definitely liked way more than I thought I would before visiting. Until you try something new, you have no idea what it will be like.

Do you think that innovation such as new rides, shows, new areas of the park or improvements to existing rides, shows and the use of mobile applications and devices could have caused you to return to the first park instead of visiting a different theme park?

For non-local parks, I have a rule that I'll always wait 3 years before I will consider a return visit. After that, if a park has added a major new attraction (either a new headliner or new section), I will add it back onto my visit list. However, I usually will not return to a non-local park unless there is also a new park in the region that I can include in my trip or every park I want to visit has installed something new. While there are a handful of parks I would still return to without this prerequisite, the 3 year rule always applies due to the number of other parks I'd like to visit and the cost of the trip.

For my local parks, I generally visit each at least once per year, and if there is a new attraction I will often buy a season pass. The only time I will not visit is if the park does not install a new attraction and does not offer any significant admission discounts.

I would also like to know how your experience was affected by the park's use of technology (e.g. mobile apps to find out wait times or to book fastpass tickets)or by new rides, shows and themed restaurants?

When a mobile app works properly, it is an incredibly convenient tool and makes it a lot easier to plan your day without running around to see what lines are like. Unfortunately, most parks do not have reliable mobile apps yet. For skip the line passes, I find the Q-Bot system used by Six Flags and a few other parks to be the most convenient and most fair system currently used by parks. For new attractions, a single new attraction typically doesn't affect my visit that much other than giving me something else to do, but when numerous attractions have been added since my last visit it can significantly impact my day and change the way I visit the park. This is part of the reason for the 3 year rule, as most parks will have at least one (and possibly several) new attractions added in that time.

I will use a concrete example of visiting two parks on one day: Animal Kingdom.

Animal Kingdom is great, but it usually only stays open to 6pm or so (maybe longer in 2016). Magic Kingdom stays open usually until midnight. There has been many times we have gone to Animal Kingdom in the morning and then Magic Kingdom at night.

I wouldn't tend to visit the same park twice on one trip if there were two parks (unless the other park absolutely positively had no interest to me at all), but if I was returning to a place I might go back to the same park on that second visit to relive the good times.

To many Parks I go 2 or 3 days in a row, simply because 1 day is not enough if you like to ride coasters in different ways like front, middle, back, looking in different directions or going blind.

Also in off Season it would waste 1 day on travelling during the 2 or 3 days the Parks are open then.