Recently watched a retrospective about the Yoshi series it made me realize that it might be one of the subtler victims of Nintendo failing to properly balance its experiments vs. rehashes. While the series rarely ever hit extreme lows (and its budgets were modest enough that likely none of the games lost money) it is one that felt like it often failed to live up to its potential for a long time,.
Yoshi's Story is probably the easiest to defend. While the focus on an easygoing time and very storybook art style was likely anathemic to some of the then audience getting sick of Nintendo's family friendly focus, it has aged reasonably well and for the time was a genuinely interesting attempt at a Yoshi title emphasizing replay. And given the company's propensity for second games in series doing their own thing (Mario 2, Zelda II, etc) the followup to Yoshi's Island being a quirky title like Story was fairly harmless in the grand scheme.
However after this things went a bit wayward. While the SMW2 remake could be understood as introducing that game to a new audience, Topsy Turvy and Touch & Go suffered from the DK mid aughts problem of being gimmick games that were made into the series' main output. A side releases between stronger entries they made sense, but as the only new releases 1998-2005, they amounted to little more than their core concepts; wacky projects that happened to have Yoshi in them. Comparisons to Kirby Tilt & Tumble do the former no favors given that series still had consistent mainline output (and KT&T being a better game) while the latter is hard to not see as something that would be a cheap/free mobile release now.
After this the arrival of Yoshi's Island DS & New Island proved to be mixed blessings. While the were finally core platformers that ended up being decently solid, neither fundamentally seemed to take the series in particularly interesting direction. The first one's focus on the babies was novel, but given Baby Mario wasn't the strongest element of the 1995 game to begin with, building on that led to an experience that while interesting at points, often felt like it lacked depth. The second was a good game, however it lacked even the exploration of the multiple baby mechanic in DS, leading to a solid yet unspectacular title.
Moreover, many of the Yoshi releases were falling into the trap of feeling infantile in tone and aesthetics. The series was always meant to be a family friendly franchise that kids could get into; its just that first game still felt restrained in being colorful while not obnoxiously kiddy for most of it. Even Story could at least be forgiven in Nintendo initially indulging an art style to make the game stand out against the 2D games still prominent in the era. Afterwards though, "baby's first platformer" felt almost literally true in some cases, as between the new Yoshi voice, reuse of Story visual elements without genuinely evolving them, and losing so much subtlety in use of colors/designs? It contributed (unfairly) to a sense of shallow appeal with the IP, even when there were games that had relatively strong cores like DS and New Island.
All that made Woolly World such a triumph. The level design/puzzles felt evolved, the baby Mario aspect was finally moved away from again, and the visual tone was creative, warm, & inviting without going over the top in trying to appeal to young kids. The physical textures for each level are brilliantly utilized, each unique theme fits the level perfectly, and the unlocked Yoshi's are so well done it incentivizes unlocking them (and therefore completion) even more. Good Feel made a game that truly built on the the original game, gave it a unique graphical identity, & even managed better pacing/fair challenge than the 1995 title did. It was the sequel the series desperately needed for so long and never got until then.
Its incredible success does make Crafted World a bit of a downgrade, though to its credit, most of its issues seem to lie in a clear change in direction during production than its core ideas being necessarily bad. Visually it looks fantastic, level motifs are creative, and even the boss battles stand out; its just undermined by inconsistent success in intertwining relatively easy levels with rewarding exploration/completion. A clearly flawed game, though unlike the franchise's previous mixed efforts it doesn't drown in its gimmick nor play it too terribly safe most of the time.
Basically I'd say its a series that like DK and Star Fox, has greatly suffered from a lack of consistently strong in house developer and a focused effort in evolving what the IP is best at. Good Feel's emergence has been a relief and with any luck they might be the group to keep it a relatively strong sub-brand, but time will tell.