Nothing's particularly WRONG with frigate, it's just circumstance seem to hate ness. The platforms are nice height, the slope on the second part is nice, it's just that the stage flip will oftentimes kill you (if you're landing after using PKT2, you go back into helpless falling state for a bit) or the platforms will take your thunder by jumping out at bad times or the platform at the right on the first part of the stage will decide to start moving up when you prepare to PKT2 onto it.
My recommended stage list:
SV -- The moving platform is what you should always be touching, and if you aren't, something's wrong with you. Even if you can't platform cancel well, just do maneuvering shenanigans.
BF -- I had some video on my computer or somewhere else describing that the platforms here are slightly lower than anywhere else, but I must've deleted it. This allows you to do some stuff rising up to the second platform with a full-hop. ALSO, the top platform can be double-jumped to and landed on smoothly if you time it right, but I haven't played in a while, so I can't tell you exactly where that jumping point is.
Delfino -- I don't know whether or not this is legal anymore, but it's ness' best non-starter stage. The water is awesome, you can manipulate the timing of lift-off and drop-down to different areas of the stage to do crazy stuff with pkt off-stage. Knowing this stage helps a lot in developing your ability to use parts of the stage to your advantage.
EVERYTHING ELSE SUCKS! Brinstar is probably banned by now, but if it isn't it's only good for gimmick and stupid stuff. If you ever go to brinstar, break the balls in the middle all the time. It only hurts you. If you ever get stuck below to recover, the ball stuff can be annoying to go through. Also, sets up pillars pretty frequently.
My other stage after the above is Halberd, just because I like stages which have go-through bases to utilize the floaty jump that ness has.
because falco does well on BF and relatively well on SV, you're essentially dead in terms of starter stages. TO THAT, YI SEEMS GOOD! Only because it throws off the falco a bit.
EDIT: Oh yeah, falco chain grabs.... When it comes to delfino, just be careful and don't play dumb on parts of the stage where he has the ability to laugh at your face.