Not really. The early G1 episodes were animated by Toei Doga which is based in Kyoto. They also animated series like Lightspeed Electroid Albegas, Dragonball Zed and many more. The reason why the G1 cartoon designs were simplified was a deliberate decision from Sunbow's design supervisor and internet troll, Floro Dery. There were actually earlier animation models created by Takara's Kohara Shouhei which were used for early toy commercials, but Dery rejected those designs in favour of his own simplified ones. Just look at the differences between Kohara's and Dery's designs for G1 Sideswipe.
Therein lies the flaw of democracy.
The funny thing is that MPs started with the complete opposite design philosophy. If you look at MP1 that toy is hyper-detailed. Hydraulic pistons on every joint, air-pump activated shin vents, working suspension on the wheels and ankles, individually articulated fingers and faceplate, foot articulation (not ankle, foot!) etc. -- the list goes on.
Another possibility is that Mitsubishi may not have been so fussy with the Fuso FT fire engine, allowing TakaraTOMY greater freedom in making the vehicle more G1 show-accurate, thus stripping away a lot of the detail granted by the vehicle mode. Other MPs may be relatively more detailed because their vehicle companies wanted more accurate looking vehicle modes (as a condition of their licences), thus then in turn added more detail to the robot modes. Companies like Nissan, Lamborghini, Corvette etc. were obviously more precise in wanting their vehicles to be portrayed in accurate detail. Even VW were quite picky considering that MP Bumblebee even sports VW logos on his hubcaps!Cos yeah, if Mitsubishi were more insistent, then MP Inferno's vehicle mode at least would look a whole lot more better than Super Fire Convoy's Hino Branbilar fire engine mode.
That's not to say that Mitsubishi don't care about any of their vehicles being accurately portrayed in toys per se, but possibly just not when it comes to vehicles that aren't available for sale to the public like their Fuso FT fire engines and cranes. It might be different if it were a commercial vehicle like the Fuso Canter or HSR III (although the odds of an MP Hydradread is highly unlikely). So it may be a case of TakaraTOMY having wanted to bring more cartoon accuracy for quite some time, but their ability to do so being influenced by vehicle companies.