While my reaction to the film was generally positive immediately after watching it, I think overall, I'm pretty mixed over the film.
I liked the cast overall, I liked their stories and I liked their bonding. I liked that they spent time with the inidividual Dinozords and most of them got some action. I liked that Pterodactyl wasn't just useless outside of being the chest armour for the Megazord. I liked that they had to coordinate to control the Megazord. I liked that it was pretty clear Rita was the original Green Ranger right from the get-go to get that out of the way.
I liked Rita overall but felt she could've done with more screen time. I thought the time developing each Ranger was uneven, with the detention trio getting most of it, while Zack and Trini was more incidental, though maybe deliberately mysterious.
I thought it took way too long for the rangers to morph and actually get into the battle. Some people liked the film before that point, some people liked it after, but it certainly made it a lot less of a Power Rangers film than it probably should've been. I didn't like Goldar and thought it was probably a waste of money. I didn't like the transition to the Megazord was bad - imagine if Transformers did away with their signature transformations! I didn't like that the Megazord had separated cockpits.
I just think the film overall misses the mark in being marketable to kids, to teens and to adults who were fans growing up. It's too dark and slow for pre-teens. It feels like a teen movie but today's teens likely grew up when Disney held the reigns and did at poor job with the franchise. Or they'd be too embarrassed to admit they want to watch it, I don't know. And for adults who did grow up with early Power Rangers, they could probably appreciate the teen drama, but I'm pretty sure most wanted to see the campy Power Rangers action too.
I mean, it most of the film didn't feel like Power Rangers. It was competent, but it felt like it was missing something. It definitely wasn't for kids. Compare that the MMPR: The Movie - that was really quite a shit movie, but there was a lot for the target audience to like about the movie. Although I was a little disappointed at how little time they spent in their ranger costumes, and how terrible the CG was, as a kid it was freaking amazing regardless.
Budget-wise, I felt they could've saved costs by making Goldar more practical and less a giant molten mess of gold. In terms of prospects for a sequel, the film seems close to doomed due to its budget alone. At the same time, I don't know if a different approach would've done any better. The CG was competent and well done and a lower budget might have negatively impacted that. But they might've been able to pull it off on a lower budget with a mix of practical and digital effects.
Overall, I don't know whether doing it differently and/or on a lower budget would have improved the film or it's prospects at making a profit. It seems Lionsgate will get its money back because of the distribution deals. Maybe it'll make a decent profit on home video from people too embarrassed to admit to watching Power Rangers. Or maybe Power Rangers is just past its prime without a clear target market.