User 4869 wrote:there was no reason to change the roles in the first place
The same reason Conan did not tell his secret to Ran. The same reason Heiji and Conan don't tell Kazuha and Ran when they went to apprehend culprit in the furikazan case. The same reason Kazuha stab Heiji's hand. The same reason Ran sneak in Jodie's car. The same reason Haibara don't tell Conan everything she know. LOVE. My lord Voldermort, LOVE.
Wait... the reason why Conan took Ayumis part in that case was... because he loves her?
As a Conan x Ayumi supporter I won't start an argument on that conclusion, though I was a bit surprised to hear it from you.

Otherwise: When Kazuha stabbed Heijis hand she was lucky that her plan did not go as expected. The DBs were unlucky that their plan did not work as they expected.
If they had succeeded, the police would have arrived normally, rescued Conan and the hostages and they would have taken an (more) important role in the case. If Kazuha had succeeded... well.
They probably don't understand this. But if they agree to did it anyway. they should follow that until the end. Not change plan, I repeat, For their own glory, not the outcome of the case.
And the remaining point. They already agree to follow his plan. If they don't want it why not speak out. What right do they have to change his plan. IT is his plan, his glory that they want to steal. Didn''t they force their friendship on him whem they first met. It's not that he want their cooperation. they just try to force themselve in.
Despite to them not admitting it, Conan is their leader. Since the plan made on such a short notice they didn't have any chance to object - especially since their feelings of "Ayumi needs to be protected", "It is scary", "Conan has the best ideas", "What a bold plan" would make it hard to refuse the plan in the moment he suggested it. The realization that their own role would just be going to the police and give them the awesome gadget Conan just gave them probably hit them later.
Had Conan emphasized that the police needs those glasses ASAP because he wouldn't have a chance alone they would probably done it. But to me it seems like he intended to take down both kidnappers on his own right from the start.
Also, seeing it from the bright side: It seems like they learned their lesson. In later cases they usually sticked to the plan.
True. May be there are just no way to give them reason not to did what they did. If you found a way, please tell me. this part bug me too. If he can reason with them them he should. The only thing I can think of now is "I am better" which would not help anything.
He has three choices:
Either stop acting so reckless himself when the DBs are around. (Won't happen, but as long as he keeps this double-standard he can't expect them - or Ran as well - to remain in the background while he risks his life.)
Or make them realize that he is better at handling dangerous situations while they should avoid them at all cost possible. (He is kinda working on this one, but despite some positive results he will never be 100% successful, especially when the DBs can't see possible dangerous consequences of seemingly harmless action yet.)
Or he has to accept that they sometimes will follow his example. (In which case he needs to prepare them better for them. Either by showing them how he manages those situation, or by passing them gadgets that allows them to handle the situation themselves or makes it easier for him to intervene.)
Coming back why some people hate the Detective Boys: Most "reasons" just seem as some kind of excuse. They could be applied to almost any other character, even the famous and popular ones. (The one who gets Conan into trouble most is... Conan himself. And the criminals of course. And a lot of other characters when they don't behave exactly like he wants them to.)
In the end it is just personal preferences. I like the "lighter" atmosphere of the Detective Boys cases, when it is about them the case isn't inevitably bound to be murderer case like with the other cast. It has a much wider spectrum from kidnappings, treasure hunts, mystery solving... well, up to the occasional body turning up.
Though, I wouldn't mind of Gosho took some effort to flesh out their characters a bit more. Ayumi just being "the cutie" that occasionally drops a hint how to solve a case by accident is not enough after so many cases with her - usually the moment when it comes to her being "Haibaras best friend" and their interaction with each other her character seems so much better portrayed.
Same with the moments when Mitsuhiko gets a chance to shine and show how smart he really is if given the time instead of just being "the reasonable".
And also the rare moments when Genta gets to show his courage or strength to prove that he can do more than just easting...