I heard the US version of Partners in Time buggers up the combat by giving the enemies and bosses more health, and weakening the defence boost certain gear gives you, essentially making the game way more tedious than in other regions. I've always liked PiT but I never played it in the US. Since the bosses already take too long, I imagine American players had a much worse experience.
Dream Team was just way too long. I enjoyed the combat but it's such a chore to replay because of the amount of useless dialogue and tutorials, which prompted them to add a fastforward button to Paper Jam, and replace tutorials with an instruction manual. Much needed improvements.
Screws up? That difficulty increase is the whole reason why PiT is one of my favorite games! And the bosses only take too long if you don't figure out the gimmicks to actually deal massive damage to them: each one is like a puzzle boss in that respect, and you can cash in absurd amounts of damage within the window given. Granted, if you never did anything like knocking away the glass from that caterpillar or knocking the eggs back into the Shroom yoshi's heart, then yeah you'll be running nowhere fast.
(for reference I've beaten PiT three times in a row, SS twice [once on release, again relatively recently], BiS like one and a half times [I have my problems with that game but that's another discussion], and DT once [Would love to tackle hard mode but the gauntlet beckons and I need another stylus])
Dream Team's pacing problem, imo, is the density of random encounters in each area combined with the game out-and-out telling you to beat every single one you come across to have good levels. The problem is hewing to those as hard and fast guidelines and not, say, a suggestion. I think a lot of people would think much better of the game if they toned the number of encounters in each area down, because the in-game combat shines at the first two to three times you fight an enemy. Not to mention the boss to trash fight ratio is horrifically skewed in the latter's favor.
EDIT: Historically, every single M&L game, including SS, has had a difficulty bump up whenever it's localized. BiS tried to exponentiate that but Bowser's just too goddamn powerful for it to matter.