The focus is on characters as opposed to toys. Toys change and there are and will continue to be countess iterations of many Transformers characters. That’s why we’re looking at the characters that go to the core of the franchise. Characters that will always be relevant and identifiable.
I think the title is a bit misleading. See I thought it was a list of the top 10 characterisations, of which Devastator and Unicron wouldn't count and some of the others would be a questionable.

But Lord_Zed summed it up well:

Quote Originally Posted by Lord_Zed View Post
I think you have pretty much nailed it as far as G1 characters go, ask a non fan about transformers and they'll often say how cool Optimus Prime and Megatron was...

Soundwave, Devestator and Grimlock are all well known because so many people loved the ideas behind them when they were kids. I'm not talking about their personality (or lack of in the case of toon soundwave)