Cult Classic: Dragon Quest, despite being the seminal JRPGs, wasn't really able to gain a foothold in America during the 90s. It fared much better during the revival in the oughties, but not enough to convince Square Enix to continue localizing much past IX and the remake of VI. It wouldn't be until Heroes that Square Enix started localizing the games again, and some of them such as the remakes of VII and VIII only happened thanks to Nintendo handling publishing duties.
Demonic Spiders: Lots of examples, particularly enemies that are immune to magic, can One-Hit Kill you, cast Sleep, Healmore/Midheal, and/or Hurtmore/Firebane/Sizzle (Wizards), inflict poison or other Standard Status Effects, and have high defense or speed stats (which makes them dodge and block you a lot, eg Demon Knights).
Hell Is That Noise: The little ditty that plays when you've equipped a cursed item that overrides the current music and comes at you so suddenly that it's entirely capable of making you jump out of your boots.
Dragon Quest V features monster catching and predated Pokémon by a good three years. However it's pretty undeniable that the Dragon Quest Monsters series was created due to Pokémon.
The concept of Psyching characters up to deal more damage actually started in Dragon Quest VII, but it was only used via special moves, and there was only 1 level of tension. Dragon Quest VIII greatly expanded on the idea and now tension is a core part of all Dragon Quest games, including spin-offs.
Unfortunately, as time has gone on, Koichi Sugiyama's vociferous support of denial of the Nanking Massacre (going so far as to buy an ad in The Washington Post about it), as well as his support for homophobia, has come to somewhat overshadow other aspects of the franchise outside of Japan, and has led to calls for him to be dropped as composer (even if that means losing the old themes) and questions as to why he keeps getting hired.
The movie Dragon Quest: Your Story has also come under fire. The trailers seemed like a straight adaptation of Dragon Quest V, and the movie did very well in its first weekend. However, it turns out that the subtitle for the movie, Your Story, is quite literal, in that the movies plot ends up being nearly identical to the infamous Plot Twist of ''Star Ocean: Till the End of Time", in which the movie is actually about a kid from the real world entering the video game world of Dragon Quest V. Not only was this not implied in any of the marketing for the movie but it ruined the reputation for the movie as a whole, and with V being seen as one of the most iconic entries in the series next to III, fans were not happy, to say the least. The movie itself would go on to tank in Box office sales in the following weekend onwards.
The Scrappy: Charmles may very well be the most hated character in the entire series. He pronounces his name "Charm-LAY", but many DQ8 fans have much less kind names to use for him. Even the other characters in the game don't like him, which makes him this In-Universe.
Porting Disaster: The general opinion of the mobile ports of the first three games. A lot of the monster sprites are either/both Off-Model and/or lazily put together, the tile work is rather grating to look at and the most of the problems with the games from the original are still present.
Woolseyism: The games released since Dragon Quest 8 have actually been blessed with a remarkably coherent localization, but contrary to popular belief the Hurricane of Puns, Added Alliterative Appeal, and general silliness of the franchise are actually taken from the Japanese originals (though sometimes rather heavily re-contextualized in service of trying to make the experience cohesive in the new language, the end result of which can be hit or miss, sometimes, depending on the player).