Well, Echoes and Corruption definitely aren't as great as a lot of people paint them. Don't get me wrong, they're solid games with really high production values, but there are plenty of iffy design choices that bog them down and make replays tedious. Prime is a much more balanced streamlined experience for the most part, although I think people tend to ignore that the quality of the level design drops of considerably in the home stretch (Phazon Mines, Impact Crater- not to mention the completely unnecessary fetch quest).
Seeing the progression of the games it's difficult not to come to the conclusion that Nintendo's heavy hand holding played considerably into the quality of the first Prime. Imo it's the only one that even begins to touch upon the complex harmony of Super Metroid's map. There are those who talk up Echoes, but I find it obtuse to no good end. The number of cul-de-sacs and dead ends is maddening, and the inclusion of holo-decoders and keys mixed with paths that hermetically seal behind you for some obscure reason make traversal a slog and dampen the sense of true exploration. Part of the genius of Metroid is that progression is tied directly to ability. Every suit upgrade doubles as a key of sorts, opening up new paths or play styles. So why put in literal key/lock situations where the collected items serve no other purpose? It's like using two stones to kill one bird.
![Stick out tongue :p :p](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Thematically Echoes is probably my favorite Prime (with the best bosses), but they really screwed the pooch on traversal and progression imo.
Corruption is a hodge podge. A visually striking one, and with (mostly) good controls, but a hodge podge nonetheless. The complete lack of inter-connectivity between the major areas is antithetical to what Metroid is about. I know some would contend that makes me a purist, but I'd rather be a purist and see the integrity of one of my favorite franchises preserved than talk myself into thinking catering to the lowest common denominator is some inspired creative departure. There are actually moments of brilliance sprinkled throughout MP3, but for every high point there's some shitty NPC ruining the atmosphere, some boss tucked in the same cut and paste environment requiring the same strafe/shoot/strafe/shoot pattern to beat, or worse yet a fucking computer ordering Samus around (a depressingly common theme these days in a series that built its reputation on freedom of exploration and lack of hand holding). Corruption strikes me as a game with great execution, but built upon a shallow foundation, and lacking a true vision for the franchise.
So I can't say the games
suck, but there's definitely reason for Pacini to self reflect and own some of the shortcomings of the series. That's something I can respect. When there's obvious talent like Retro behind a project it begs the question why certain things go awry or what the decision making process is. I have my own thoughts and theories, but it's always interesting to hear something straight from the horse's mouth.