Preface by saying I like the show. It's a wonder that the writer/artist managed to come up with so many unique mysteries and puzzle boxes within with mysteries taken place. You could argue that Detective Conan is TIMELESS based on,

a. The amount of time it's been running, and
b. The fact that every vignette/arc(s) are self contained.

But Conan has some glaring issues such as,

1. His girlfriend never dates other men. Her boyfriend disappeared as far as she is concerned, one ep I saw coming back for half an ep before "disappearing" again, and the most loyal woman in existence has a limit to her patience. Also, you only consider that they're playing a prank or something terrible happened to them but for so long bf you move on with your life not out of wanton lust or even wanderlust, but out of necessity.

1a. I also don't understand why he needs a girlfriend for the show to function? Why not NOT write in a long-suffering girlfriend since her role isn't important anyway, other than to show what he's "missing out on," by being in the body of an 8yo. And the missed out on aspect is ultimately meaningless bc it doesn't drive the MC to figure out who poisoned him, which is the main mystery that the show's never bothered to answer.

2. There are no consequences to him becoming a child other than ppl taking 3 seconds instead of 2 to believe him when he was a teenaged detective, which you would think would be interesting on its own. You can almost picture the writer considering what would be more compelling. Detectives are as old as film noir, teenaged detectives are somewhat interesting if unheard of, but a child genius who no one takes seriously until the end is endlessly fascinating. And based on how many movies (24!!), spin offs (vs Lupin 3rd for ex), remasters, let's not even get into the merch, etc, you could argue that he's not alone in that perspective.

3. It's hampered bc it's stuck in that one year for over 1k eps. It allows the writer/artist to focus on the mysteries that have made it such a long standing property, but he's never had to stretch his storytelling muscles and come up with a conclusion to the mystery of who made him a child, to what end (who benefited from him being a child?), and how he claws back to his older state. Also, if they go past a year the boy grows just like he did previously and at some point in the future his girlfriend moves on to a boy her own age (this happens IRL and the show pretends it doesn't) and he becomes the teenaged detective once again, which I'm sure would raise more than a few eye brows.

"Hey, doesn't he bear a strong resemblence to the hot shot teenaged detective who went missing a decade ago? The #1 detective in Japan?"

It's not like the MC was one of the best teenaged detectives, he was THE teenaged detective. They even go a bit into the organization that wanted him gone but you can count the number out of 1k eps they've chosen to directly address it on one hand of a man missing a few fingers. Berserk, you could argue, is taking decades to get to the conclusion but it's getting there. The original artist, Kentaro Miura died and it's still getting there. GRRM and the ending of the story is taking FOREVER, but you know he at least knows the ending, if not how to deliver it in a satisfactory manner. THIS property looks like the writer saw how profitable it was and decided to never finish the story on purpose, which is much more of an scathing remark on the character of the creator than the two previously mentioned cases.

I DO like what I've seen, but talking to ppl who've seen 600-700 eps, to a person they say that 98% is filler arcs, bad guys/girls of the week.

If he had 2 full vignette adventures a day, you still wouldn't be able to account for the 1500+/2= 750+ adventures he's had within a year. The only explanation, including the stability of the casts' lives, is that they're all taking place in the same space of time, which makes 0 sense and is really silly, actually.