ok, this matchup is definitely not 65-35 olimar. i believe this matchup to be 50-50 if we were giving numbers. both of us can do some EXTREME damage to the other if we get in the right positions.
it's all about not letting the snake get into our bubble, if he does we are at a disadvantage enough to where there isn't really a whole lot of options for us to get away. if the snake is good, one dthrow can lead to a severe amount of damage on the oli unless the snake screws up.
snake can ftilt pretty much every one of our moves up close, i believe we can usmash oos if we react quick enough to it, but a lot of the times the snake will just get a free grab.
we can't grab him usually because if he ftilt/utilts right as we grab we get knocked out even if we grab him.
this is completely about how well the snake can time his moves against olimars, and how well he can deal with recovering from the air to the ground without taking too much damage. the only times i can seem to effectively give damage to a snake is when he recklessly tries to approach, but all the snakes i fight now are used to the matchup and aren't willing to approach without some sort of way to stop us from attacking his approach.
IMO, if snake players have a problem with this matchup then learn your options better, it's a pretty simple camping game on both parts until someone messes up, as soon as there is a mess up then someone gets hurt =)
EDIT: this is one of the matchups where i have the most experience, so i'm not just saying this, i may not have explained much but i can probably get a lot of videos on this matchup for how the snake player is supposed to play it =)