Ah ah, you're not totally wrong, Wario's F-air is not Sheik's one, but in some angles it can combo if you're opponent don't DI or react well. ^^
Actually, I find Wario's grab game really good, it does a lot of damage apart for back throw and the angles are generally favorable, forward throw is one of the best of its kind to K-O.
But the problem is that any of his throws are able to combo, this is often a 50/50 situation, but it's quite normal. Wario is a Bait & Punish character and he has to anticipate his opponents behaviour. Does he will attack, air dodge, tech or jump after your throw ? This makes Wario a complicated character to play.
Wario's Bike has a lot of options, if you opponent likes to do aerial attacks, you can use your Bike but in a slow motion, maybe he will try to attack to eject you because he thought that you would accelerate with your Bike, after his miss, this is the moment to punish, you can even rise the Wheel for extra damage.
As you said, bike on the stage can work as a baiting, but it's better to have your "weapon" close of you at the ledge so can throw it. There are several angles for this, but you will probably often throw it upward, this is useful before a up-throw.
You should'nt be afraid about missing your Bike, Wario's recovery is decent even without his waft.
I can advise you to Watch My Smash Corner videos about Wario on YouTubei f you didn't , he provides a lot of tricks about this.
Here is a good one for you :
https://www.youtube.com/watch?v=faMvl0XYXAc