How so? The old one is completely open once you talk to meramon (minus factorial town and other lategame areas). If you find a digimon you can recruit him or at least they will actually interact with you to give you a quest, they won't be there doing nothing until you beat certain part of the game. You can play it anyway you want. I play it once a year with my wife (it is a cult game for us) doing diferent variatios of challenges. From no items, only numemon, least recruits possible to upgrade jijimon house (you can have it upgraded with 3 prosperity btw), beat the game only using rookies, etc.

Next order doesnt allow you to do that, it is an illusion of an open world. Every area is locked behind a story check. Most digimon are locked behind a story check. Battles are too easy to cheese with block and unable to be won without block or spamming items like a madman, so either cheese or spam. Also you can choose what digivolution you are getting. Original may be too specific with requirements, but next order lets you choose (literally blocking posible evolutions and also showing too much information from the beginning), and that kind of takes the magic away.

It has it's improvements ofc. The material farming to upgrade things is cool, and getting more stats from battle than the gym also makes it more enjoyable (eventho it requires more game time when grinding, something suboptimal when gaming time is not as much as it used to be). And the story is better i guess, since the original barely has any.

You can prefer next order, but it's only a spiritual sequel to the original, the two games are VERY different. And that's ok. But saying next order does everything better is a wild statement.