Yeah mine's changed too.
Lucas: An absolutely amazing character. Special moves may be stolen from Ness, but the extra effects they have make him infinitely better. Also his smash attacks aren't useless like Ness'. Up + A ftw.
Samus/Zero Suit Samus: Neither of them are powerful enough to take down opponents alone, so my strategy involves juggling both inbetween beatings (ZS Samus) and KOs (Samus).
Diddy Kong: I love this guy. People say he sucks, but they can all jump in a lake. His facerape attack rules and his Rocketbarrel Boost has great recovery.
Mario: In the middle of all my mains is the balanced one. He's the same as ever, except his Down B move sucks.
Falco: I hated how much they changed him from Melee, but after some practice, he's even better than before.
Olimar: He's great but all his best attacks rely on having all your Pikmin present, which makes using him a gamble everytime.
Marth: Relatively the same as his Melee incarnation, but he feels way weaker, and his Side B no longer helps him recover. At least it's even easier to combo now.
The ones who I rarely or never use are Zelda, King Dedede, R.O.B., Snake and Pit.