I read an article about the 9 Worst Avengers yesterday, and for the heck of it I wrote up my own Worst 9 Avengers. Since it's a little slow here (and the next Abandoned Legion isn't finished yet) I thought I'd post my list.

Anyway, my list of the worst 9 Avengers, in no particular order, would be the following. Keep in mind my list does not include those who were just on the Dark Avengers line-up (since they're not Avengers in my book).

1. The Sentry
- The Sentry is supposed to be the most powerful being on the planet. He's also mentally unstable. That is a bad combination, in my mind. So rather than focusing on getting him help, he is added to the roster to keep an eye on him.
The Avengers need to be able to trust each other. Captain America has stated before if personal business doesn't affect the Avengers, then it can stay private. But if it is a matter that affects the team, he needs to know about it, since the team is trusting each other with their lives (this was around the time Ms. Marvel lost her Binary powers and became Warbird in the Busiek era). How can you go into battle not knowing whether the atomic bomb strapped to your back (AKA The Sentry) is going to explode or not?
He was a terrible teammate; if there was a big threat, you didn't know if he was going to come out and help you or stay at home and cry on his couch (World War Hulk).
I can't believe that Captain America would allow an unstable person that powerful on the team without at LEAST having a powerhouse like Thor around who might be able to contain him if he goes nuts.

2. Dr. Druid
Right from the first time I was introduced to Dr. Druid I didn't like him (during the class "Under Siege" storyline by Stern). He struck me as being really creepy, and his constant undermining of Captain Monica really drove me to dislike him. When he died I was a happy camper.

3. Wolverine
I actually don't have a problem with the concept of Wolverine being on the Avengers, it's the reason why he's on the team and the logistics of it that bother me.
Wolverine was brought onto the team by Iron Man to be the team's executioner. Iron Man felt that when a situation presented itself where killing was required, it would be easier with Wolverine around. Captain America argued a bit, but relented fairly easily in my mind. The same Captain America who was outraged that Iron Man led a faction of Avengers to kill the Supreme Intelligence during Operation: Galactic Storm, I might add.
Killing isn't supposed to be an easy solution, it's supposed to be the last ditch option. If you compare it to his battle with alcohol, Tony is just bringing an enabler into the team.
Then there is the fact that Wolverine is on the X-Men, leads X-Force, and conducts the Broxton Philharmonic on the side (okay, I made up that last part). In what is supposed to feel like a cohesive universe, how are we supposed to believe that Logan is able to participate on all of these different teams, especially when the X-people are now based on the opposite coast?

4. Namor
He's only had a couple of short stints on the team, but that's part of the problem. It never takes long for Namor to get caught up in Atlantis business, or decide that he no longer wants to work with the surface world, he wants to conquer it.
The other problem with Namor as an Avenger is that if the battles don't all end up conveniently near a body of water (which they usually do, this being comics), he quickly becomes ineffective. Stingray suffers from the same problem; water-based characters rarely work on teams long-term because you can only have "trouble at the docks" so long before the reader tires of the effort to get the battle near the water. Aquaman might be the one exception to this, as he has served on the JLA for decent stretches of time, but it does mean the writer has to find a way to include a body of water in the stories.

5. Mantis
I've never liked Mantis. Because I don't like Mantis, I usually avoid re-reading stories centered around her. So her inclusion is basically because I really can't stand the character. Sue me, I never said things wouldn't get personal.

6. Jack of Hearts
After his first story arc, Jack just spent all of his time locked in the Zero Room because he was going to explode. Yet somehow the guy locked in a room took up a lot of page space in that time. His rivalry with Ant-Man (Scott) felt forced, like when the writers changed (I think it was Geoff Johns who used him first, then *ugh* Austen took over) a switch was flipped and Jack went from grateful to the Avengers for help to a big jerk.
His death scene was also terrible. Yes, he saved Ant-Man's daughter (though really, Scott couldn't handle one guy with a gun? Approach him at ant size, then grow and take him from behind, shouldn't be too difficult), but then he flew the guy out to space to blow him up. And Ant-Man looks up in awe and remarks "He was an Avenger".
Avengers don't blow up civilian threats in space!

7. Thunderstrike
I'm actually a big Thunderstrike fan, I love his solo series (I just need to find #23!). But though his solo book told me he was an Avenger, we almost never saw him in the Avengers book. To me he was a lip-service Avenger only. He never really felt like a member of the team.

8. Masque
Why was a clone of Madame Masque determined to be Avengers material? Seriously? Whether you rate her by moral fiber, combat skills...she doesn't make the cut. She has goons to do her heavy lifting for her.

9. Starfox
I never found Starfox to be that useful, especially considering he is an Eternal. He has the same abilities as Sersi, as I understand it (he was able to molecularly restore a team of Avengers rendered "inert" by Sersi to survive the Nega Bomb in Galactic Storm), but he always struck me as being fairly useless, not a potential powerhouse like Sersi.
And yeah, his "love powers" are pretty creepy, though I admit, would that same standard be applied to him if he was a female character?