I think a majority of old fans are still curious enough to try this..
OTOH, I remember the Transformers cartoon sucked after Optimus and co died...and they tried to replace him with "Hot Rod". Hot Rod sucked... and "Ryder" might be the same. They basically destroyed the whole Transformers universe and no one got over it. So it finally came back. And eventually came back bigger than ever too.
I'm going into ME:A like some Trekkers did with Star Trek: The Next Generation with cautious optimism. Can Ryder become the ME:A version of Captain Picard while Shepard will be the ME version of Captain Kirk, or like Commanders Sinclar, Sheridan, and Lochley on Babylon 5? That might be a better analogy since Mass Effect 1-3 are a lot closer to Babylon 5 than it is to any of the various versions of Star Trek.
As a lifelong die hard Transformers fan I think you're off here. While Optimus Prime's death did hurt the series, and Rodimus Prime was never quite as popular as Optimus Prime was or is (he does seem to have picked up a lot fans over the years though) the simple reason season 3 of the original series, which IMHO had some best scripts and stories of the original series, it was simply Hasbro was constantly making radical changes the franchise to keep it going with weird gimmicks like the Headmasters, Targetmasters, Powermasters, Micromasters, Actionmasters, The Pretenders, The City Bots, The Sixchangers, etc and the franchise at that time only had the cartoon show and one ongoing Marvel comic book to support the fiction and the cartoon show just really couldn't keep up, I mean the final 3 episodes had to introduce the first wave of Headmasters and Targetmasters which was something close to 40 new characters in 3 episodes while also trying to give the recently revived Optimus Prime a major part and a lot the better written episodes were made by an awful sloppy cheap animation studio also didn't help. While the comic bent over backwards trying to cram as many of the new characters and concepts that Hasbro threw at them has they could and it's nothing short of a miracle that any of the Marvel Transformers comics are readable today and that original cartoon show is even watchable. Also many of the first wave fans who were 6-9 it could in 1984 grew up and were becoming pre-teen and teenagers and finding new interests and hobbies and other new franchises like TMNT, Batman, and Power Rangers were coming in and getting the younger fans that they needed at the time.