Ironic. Rengar is worse than Teemo and people beat on him. XD
True! ...at least I think?
If what you meant was that Rengar is actually fairly weak compared to Teemo (and a lot of other champs) but people hate him (Rengar), then yeah you're right.
A fed Teemo doesn't make 75% of your game in black and white. So no, Rengar can be stronger than Teemo if he's smart. Assassinating him is an option if you can't get an adc.
Permit me to discept. Remember me? The RENGAR TOP main? Yeah. Jungle... I suppose then you're right, but toplane Teemo is brush control hell.
That's why you get a sweeper and sweep the jungle before getting in...
Or smite birds and reveal dem shrooms.
Either way, you have a way in, you just have to think how.