I'd say it was a response to people who kept on pining for more mechanical and vehicular looking Transformers. The "Trukk Not Munkee" crowd was an extremely vocal minority. Hasbro launched Machine Wars which failed, so I'd say they came to a compromise where they continued with beasts, but these would have robotic beast modes but bestial robot modes, as well as intermediate vehicular modes.

It worked out in the West but the idea flopped in Japan where a lot of fans didn't like Beast Wars Metals as they found that the concept made the Beast Wars Transformers no longer robots in disguise. A robotic gorilla isn't a realistic looking beast mode. This is why Takara went with more realistic looking beast modes with the Japanese BW lines, especially BW Neo. Some of the BW Neo Transformers were actually based off fan designs submitted via competitions; such as Mach Kick, Archadis and Bazooka. Star Upper (see Paulbot's avatar) was a competition winner that unfortunately wasn't made into product, but the character did appear in the manga series and made a cameo appearance on the TV show (only as a background character and only in beast mode).

BW Neo really gave us some fascinating beast modes likely to be never repeated. What other series has given us a Transformer who transforms into an extinct species of marine mollusc!