How much of the second arc was planned?
Not an awful lot. Furman would have stayed on, but it seems the comic’s cancellation was seen from far enough for no real work to be done towards further issues. The writer has since admitted that several things, such as the Liege Maximo and his claim to have spawned Megatron, were just thrown in to tantalise. However, the UK semi-official fanzine ‘Transformers Continued Generation 2’ [see here], and the other output of British fan group Transmasters UK, have produced a vast body of work following on from the end of the series. While it’s not official, if you want to hear some fantastic solutions and continuations of the mysteries of the series, it’s well worth a read. Furman himself continued the story of the Liege Maximo in the UK convention Transforce’s text story “Alignment” from 2001/2002.