I've played most of it by now. In many ways, I loved it; it had the Mario and Luigi spirit of the first two, and the graphics, plot, and abilities were hilarious. I was very glad to see Fawful as the primary antagonist, and the two Shroob cameos were nice too. I also really loved how you could play special-attack-oriented minigames and replay boss battles in the Gauntlet. What was more, certain aspects of it were more reminiscent of Superstar Saga than Partners in Time, which was a plus.
My main problems with the game:
1. It's too short. There should have been more areas, and the existing areas should have been longer. Though I am glad that you need to return to some places to get everything--a feature that was almost nonexistent in PIT--there wasn't enough of that. Bottom line: Superstar Saga was longer and had more areas, and Partners in Time had bigger, more varied levels.
2. You can't increase your stats indefinitely. In Superstar Saga, you could always improve your stats by blending bean drinks at the Starbeans Cafe--and you could win more beans in minigames. Partners in Time was even more guilty of this--In that game, there was no way whatsoever to upgrade your stats (besides leveling up, of course!), which meant that once you reached level 100, that was it; there was nothing more to achieve. When I first learned that there were beans that could up your stats in Bowser's Inside Story, I was very excited, but my hopes were dashed when I learned that the number of beans in the game was limited. While we're at it, the bonus point stat system really frustrated me in this game. In the previous two, you could get almost indefinite streams of high numbers as long as you were always careful to alternate which stat you allocated the bonus points to. In this game, the only way to get a really high number in a stat is to neglect that stat for several levels.
3. The whole plot of the game seems kind of rushed; you rarely had to go far out of your way to do something. This problem has gradually increased with each game. To illustrate my point, I'll use the example of Mario and Luigi's hammers. In Superstar Saga, you had to hike up a huge, tall mountain to find a rare stone that the Hammerhead Bros. could use to make hammers for you (and rescued Prince Peasley in the process!). In Partners in Time, you had to beat the Hammer Bros. to get hammers for Baby Mario and Baby Luigi. In Bowser's Inside Story, you just break open a crate in the Trash Pit. This is pretty much how most of the plot went.
4. The field moves were okay, but they could have been better, and there could have been more of them. I was glad to see Mini Mario brought back, but it was stupid that you couldn't switch to Luigi when they were separate. Come to think of it, the whole game might have been better if you could switch the bros like you could in Superstar Saga--it would have allowed for more plot twists and more special moves. I immensely enjoyed the part where Mario got carried off by a band of Sockops, leaving Luigi to wander around solo, but there should have been more of those...and there should have been more parts where Mario had to rescue Luigi, too.
5. The music and sound effects were worse in this game than either of the other two. The tunes were very repetitive and got kind of annoying after a while...and Fawful's theme really left something to be desired, compared to Cackletta's creepy organ music and the Shroobs' sinister drum beats. The sound effects were okay, but most of the best ones were sounds that were recycled from PIT; the new ones were forgettable.
Personally, I think that the ultimate Mario and Luigi game would have length, abilities, and plot advancement in the style of Superstar Saga, graphics, music, and sound effects similar to those in Partners in Time, and minigames, gear system, and interface like Bowser's Inside Story. I don't think we'll ever see that, though.
