G1 Cancellation didnt bother me as much due to the line actually having an ending done trough a comic (even though I think the stars were kinda pointless as sets due to the Av Matoran build). Bionicle ended at the time when I was worned out with the theme, which contributed to me not having a problem with its passing. It had to have ended at some point. Also a fair note, I never read the expanded comics, books and similar media that wasnt available for hte wider audience (which were the movies, commericals, the site, and games), so to me I didnt care much for the in-depth story primarily cause I had no way to access it freely and easily from where I lived.
I didnt really like HFs first hero sets, mainly cause they just used a slightly visually different Av-Matoran build, the Villains were nice and I can see them usable for Bionicle stuff. In terms of Marketing I always felt the notion that HF was set in the same universe as Bionicle or possible even the same planet of Spherus Magna just in the future, and I kinda still stick to that fanon cause the story holes and elements just fit for me like that.
I had almost bough a HF set, specifically Rocka Breakout series one due to it closely resembling Kopaka in Gold armor and having descent color scheme with back coverage....however no HF set has ever truly interest me to spend money on due to each set having some flaw that made me not buy it...then G2 came along and fixed almost all those gripes with the Masters (even though I later on went on Bricklink to get some Modification parts for them, but more or less they didnt need too much to be changed). Overall HF had a lot of potentional as a successor to Bionicle, Breakout year was the way to go and if it hold on to those kinds of set design qualities, story, and thematic aspects, HF would have shined....but LEGO seems to fail in those aspects.
When it comes to the design of each years of heros the best was Breakout, followed by Invastion from Bellow (despite my innitial negative thoughts on the minifigures in what was once a primarily constraction centric theme...now I appreciate the MECH builds more), then Brain Attack (descent builds, but lower than the first two due to the color and design choices), then Rise of the Rookies, then the Ordeal of Fire, then Savage Planet. The last two mentioned felt less LEGO like of them all due to CCBS only being released and the pieces used felt very different from what we were use to, I didnt mind the balljoint aspect of it, I just didnt like the weapons, torso addon, and the helmet with the heads (the mata nui looking heads were a crime against nature, they didnt even have light-piping).
The Villains were always way better and larger than any Hero set (quite the opposite from Bionicle), but since I dont like villains that look ugly, most of them right upfront didnt appeal to my sense of aesthetics. If I was a dedicated mocist, those sets would be amazing for me.
I am quite glad HF existed, it brought tone of new and interesting pieces, new building system that is objectively better than the undefiend Bionicle one. However I am sad that the community aspect of HF and to an extent Bionicle has sowered the reputation of the building system in the ways it really didnt need since it was a line that already was not as popular as system (we didnt need inner civil wars about it adding insult to injury).