Fun fact: Everytime someone from the fandom trying to fix the old Jedi Order, they are promoting exactly those things that led to it's downfall in the form of Anakin Skywalker. Did they even watch the movies?
> the Jedi need to allow people to marry.
Anakin Skywalker married, and it was one of his main driving points to abandon the Jedi Order.
> the Jedi need to allow older people to be trained.
Anakins connections to his family opened him up to strong emotions and the Dark Side.
> The Jedi were afraid to use the Dark Side and to open themselves up.
Everytime someone uses that sentence in universe he has a above 50 chance to completely fall to the Dark Side and loose everything.
If one wanted to argue that the old Jedi Order was bad, then because they did not follow their very simple code and their gut feeling. Every single time they went against it, they dug their own grave.
What they should have done:
> When Anakin wanted to become a Jedi
Follow the code, throw the kid out asap.
> When the Republic wanted them for the Clone Wars
Follow the code, Jedi are protectors of peace not warriors etc. They had nothing to win being in there.
The system of the Jedi code was working for millennia. The reason it failed 19 BBY wasn't because a disfunctional system was applied, it was because a very functional system was completely ignored repeatedly