Right manveruppd this is where things get complicated...
Transformers originally aired as 4 seasons in the US & UK & the timeline went something like this...
Season 1 & 2
The Movie
Season 3 & 4
Season 4 was short & bascially culminated with the three part Headmaster Episode & ended the US saga there.
However in Japan
They were done in the following time scale:
Season 1 & 2
Scramble City OVA (Bridges time between end of season 2 & the movie)
The Movie
Season 3
Headmasters (This replaced the US 4th Season as the Japanese didnt take to the way it finished)
Masterforce (Introduced us to the Power Masters)
Victory (Brought in the Pretenders)
Zone (Single shot was meant to be a series but cancelled after 1 episode
)
As far as where it originated I'm still not 100% sure I do know the toyline was solely a Japanese thing until the time when Hasbro bought out Takara & licensced the toys as Transformers, then the Cartoon followed shortly after.
And like you I feel alienated byt the last few seasons of TF as they just dont seem the same ok they have the same names (Starscream, Prime, Megs, Galvatron, Ironhide, Mirage etc.) they just arent as robotic & having to "Advertise" what their doing all the time ala Pokemon??
Hope that helps to clear some of it up?
Neil