It's all positioning and stage control. If olimar can keep up with rainbow cruise to a point to where he cant get gimped, the stage works well for him. Not that it's a GOOD olimar stage, but it's not destructive. If olimar gets knocked off of a platform on RC, two things can happen. Either he lands on another platform, or he falls to his death. This is all dependent to where he is before he got his, so predicting this and staying only where you're safe is extremely important. Also, remember that after the pendulum phase, he no longer has the dangerous problem of getting gimped like in most areas. Granted, playing characters like Meta Knight or DDD here is a bad idea, but against a lot of other characters, the stage isnt a problem. But olimar's camping ability is amazing on the stage, as he is still able to camp just as well, while it's made more difficult for most others.
Frigate Orpheon is bad for him due to the right side on the first phase. However, there's several good points to the stage as well. Say you're fighting a peach, in which all of the good stage qualities for olimar come out against her. Frigate spawns an increase in purple and yellows, which are good against most characters, notably peach. Peach gets screwed by the right side, just like olimar does. In the second phase, peach's inability to gimp olimar off stage well, after knocking him off is a problem for her, as the platforms on the sides will come out to save you. Also, the dip in the second phase works great against facing her. There ARE things that olimar can take advantage on in this stage, and several characters that Frigate works well against (DK, Marth, etc)
Japes is a problem for several reasons. The main reasons are that the high ceiling makes killing vertically next to impossible, and the left side is extremely dangerous as getting knocked off there usually means death, as regards to the right where olimar is able to pop up on the left side after getting dragged by the current. However, I do not consider the water a legitimate reason to call japes a bad stage for oliamr, whether or not the current is going to kill you. If you fall of the stage in almost ANY stage and get edge hogged, you're going to die. Japes' left side is no different, neither is it worse. I've found myself camping the right side several, several times while my opponent's on the middle platform, and when they try to approach, I drop below it, uair through the platform and regrab the ledge without having to use tether.
I would, in my opinion, say that japes is olimar's worst stage, followed by frigate, then rainbow cruise. The reason i'm so casual about talking about them and not acting like they're extreme problems, is because of how much i've played them, and how much i know the stages. I know which ones to ban against what characters, and, for the most part, how to play the stages right so that olimar doesnt get messed over by them. As for his best stage... probably mansion, maybe lylat, and i've been playing around with halberd quite a bit and it's pretty amazing for him.
Sorry, lucario boards, for using this thread for olimar discussion
Just to wrap things up Lucario Boards, my opinion:
Neutrals
Try to take us to Battlefield, if not, yoshi's island
Dont let us take you to FD
Olimar's Counterpick
You'll want to ban either Halberd or Norfair against us, depending on preference and the olimar's opinion on where he's comfortable going. This may be inacurate, and i'm not sure where most olimars take Lucarios. I often just take them to FD and Halberd, as I dont really like Norfair, but I could see how it would work against him.
Your Counterpick
Taking us to either frigate orpheon, japes, or battlefield would be your best idea. All are great for you for different reasons