I noticed that twice, three times if you count two different treatments of Tron: Legacy, I've said that I think movies could be better in a TV series format. This is not some thing where I think a TV series automatically works better, if anything it's an artifact of me watching movies more often than TV series.
Tron: Legacy would be a good candidate for a series because what it needed was more depth, but not just because it needed more depth. It needed more depth in a certain way. The problem wasn't a lack of interesting things, but a lack of delving into those things. It scratched the surface of a world full of depths waiting to be explored and ended up as shallow as that depth. While a decent story could be told in feature length set in that world, the world itself never could be properly explored in such a short time. The movie was much more about the world than anything else. Hence it could have used the additional time that would be offered by a series, instead of scratching the surface of multiple interesting ideas but exploring none of them, it could have explored the ideas at leisure because there would be no rush to finish off everything in a mere two hours.
When I said that I'd have preferred that Now You See Me be followed up with a series it was for entirely different reasons.
With now you see me I see the potential for a show like The A-Team, Leverage, or any others of that ilk. Someone is fighting for those who have no where else to go. The little people who get crushed by those who are above our outside the law. Now this team can deal with them.
With Leverage they focused on thieving. Nate, who had been catching thieves for ages, made the plans because he (by virtue of having been on the other side) could see not just the plans that incorporated the others skills, but also where those plans would go wrong. Elliot's skills were in the "beat people up to steal stuff" arena, Parker's in the just plain steal stuff and don't deal with people at all, Hardison's in using computers for theft, and Sophie in pulling a con.
With The A-Team their background was military but they still had a diverse skill set. Hannibal made the plans, Face did the cons, BA was the muscle, Murdock was the pilot.
With Now You See Me one can imagine a team made out of freaking magicians. All are good at slight of hand, one can pick pockets and locks, two are good at the standard misdirection that lets you apparently disappear from plain sight and appear somewhere else, the forth is so good at cold reading he makes it look like real magic, the fifth can pull of a fake persona like nobody's business, and they've got two non-magical contacts: one in the FBI, one in Interpol.
Oh, and after the first movie they're supposed to get access to actual magic.
I want to see this team helping people. And that's best served by an episodic format. Note that the reasons for thinking Tron: Legacy would do well as a series had nothing to do with episodic format and everything to do with the greater ability to delve and dwell that the length of a series gives one.
But the flipside is definitely true too. With all of the complexity of Middle Earth it might have been better served by being a 20 hour miniseries, but the only actual 20 hour mini-series I've seen (Sci-Fi's Taken) was mostly plodding through padding to the point I'm not even sure if it could have reasonably filled a trilogy. It might have been better as a single made for TV movie.
I'm not going to mention it by name since I didn't see the whole season and thus shouldn't pass judgement on it, but I watched the second season of a TV series where it felt like the thing would have done much better as two hour movie.
I was unable to make it through more than two episodes of Charlie Jade, and then only because they were run back to back, because it didn't have enough content for its format. The first episode could have been told, with no loss of worthwhile content, in about two minutes. The second admittedly did have more content, but not enough for me to watch a third.
The point here is that because I watch more movies than I do series I'm going to more often comment that a given movie would be good a series than the other way around BUT the other way around is likely true just as often.
If something merely scratches the surface because it doesn't have time to delve into the interesting things it presents, it would be better served by a format with more time. If something plods through padding it would be better served by a format with less time.
If something would benefit from an episodic format, then obviously a TV series is right for it. If something is best told with a tight focus on one thing then it should be a movie, miniseries, trilogy, or something of that nature. Trying to stretch it out into a series just won't work. (What can work is making that the background while having the bulk of the series devoted to something more episodic.)
Reasons that movies would work better as series are the exact same reasons that some series would work better as movies. They just have reversed directions.