Stingray? He was an Avenger for all of 5 minutes. D-Man was barely even an Avenger at all, and annoyingly, Century never actually joined at all.
Deathcry/Rage/Tirthlon were all deliberately written as abrasive for the first half of (or in Rage's case, most of) their time on the team, so it's no surprise that they're not really very popular with readers, and Druid even more so. And yet the "reasons" this list gives are pretty poor. They either knew who Century was, or did some research, and yet he and Deathcry both get "LOL 1990s suck haha" and that's it, aside from the continuation of the bizarre notion that putting an alien on the Avengers was "making them more like the X-Men"? And yes, Druid was a fat balding guy, and yet he actually WORKED during his time on the team, because he didn't need to be in fighting shape or have hair to use his mind powers, and he played the team like Tetris and took them over, and that was some Grade A Awesome.
Silverclaw and Gilgamesh were indeed terrible, however, I'll give them that, and Sentry is the only real "major character that Marvel devoted serious time and energy into Trying To Make Him Happen who was nonetheless massively unpopular" that's on this list, and THAT'S what I'd rather be seeing on these lists. Stop taking cheap-shots at D-listers and the guys who never quite made it, stop thinking you could get a whole other 10 out of Lionheart/Swordsman 2/Marrina, Masque/Darkhawk/Machine Man, Jack of Hearts*/Sandman/Two-Gun-Kid and Whizzer, and do something more relevant; the characters who have had enough staying power in the Avengers franchise, that there's a very real chance that they might show up in movies, but we shouldn't want them to, because they're boring or just awful.
Seriously, how many of these "lamest Avengers" lists have been put up onto the Internets over the years, and they all take the same quick and easy route of laughing at the guys who never made it, and singling out the intentionally-dislikable characters as thus being "bad characters we don't want to see."
I'd much rather see someone bring up the fact that like every other super-team, the Avengers have characters who, by inertia of always being around, or by being around during a large segment of the audience's formative years, are accepted as being important members of the group, who we'd expect to see show up eventually in any adaptation, from cartoons to movies, and it's harder to register that they either never really do anything to justify their prominence beyond "they've been here for years", or that they're an aggressively terrible character whose very presence is poisonous to the series. What I'm saying is, aim higher, take shots at Tigra/Starfox/Wonder Man, even Wasp, if we dare.
H*ll, Spider-Woman 1 is on the "Avengers we'd like to see in the movies" list, and whatever she did or didn't do back in her old solo series, everything she did as an Avenger that mattered at all, that was all Veranke. Putting the real deal on the team after Secret Invasion seems to have been a mistake, since she's just...there.
* - but seriously, why is that tool not on this list?