If Enzeru was here he would sure like this. A poster from CV named Mazeraii made a very good argument that the Deathseed is not a power amp, but just makes the Sentry sane and unlocks his true potential. This is the scan he posted. (please log in to view the image)
So it seems Deathseed Sentry's feats count for regular Sentry.
It's a hard thing to argue because Remender has mentioned Sentry being souped up before with the Death Seed.
I was talking to Enzeru about this exact thing a couple of months ago but it seems Remender has him amped. The only thing I really argue is it's hard to tell how if he was amped then how much, because a Sentry without Agoraphobia and fully Stable has a gargantuan power level. Something which we haven't really seen in comics.
The closest we come to a Stable Sentry would be him in Vol 2.
Actually Rick's words can be interpreted anyway. According to the scan by the deathseed unlocks the hosts minds to use their full potential. Thus they are more powerful than their normal selves. For example... It is said Storm has the potential to be omega level mutant and it has been stated many times. With the deathseed she may be because again according to the scans it unlocks their true potential. Same thing can be said for the Hulk using the deathseed.
Rick didn't specifically state how the Deathseed increased Sentry's powers. He just said the Sentry will be more powerful. He could easily mean the Sentry will be powerful in that he will be using his true potential compared to other times. Since his mind is now sane. That is what Rick could have most likely meant.
Don't get me wrong I hope you're right. It's just we need to be doubly sure before we concretely say something is true. Because then that ends up with the Sentry being a Multiversal reality warper posts.
The following scans are all from the handbook, which comes along with the Sentry figure from the "Marvel Comics Superhero Collection".
http://i.imgur.com/M95veWX.jpg "The Avengers had already mucked up with one reality-warping super-friend and they weren't about to let it happen again."
As already covered up briefly in this thread, Sentry's actual power set is the ability to warp the reality. This handbook implies that as well by mentioning Scarlet Witch as the first reality warping teammate the Avengers had to go up against, and their attempt to avoid the same with the Sentry.
http://i.imgur.com/lBWrS6V.jpg "He would join the team, where they could train him and keep an eye on him so he wouldn't go all 'Scarlet Witch' on them."
The handbook also directly refers to Scarlet Witch and the safety precautions, the Avengers had, regarding the Sentry.
By now it should be clear that Sentry's power depends on his mental state. This handbook mentions it as well.
However, wording it "confidence" is maybe not the best way to describe it, since the talk is usually always about phobias and anxiety. Although it still fits in a way, since having a panic attack or even just being anxious / phobic, is pretty much the opposite of being confident.
Later on Sentry's fluctuating power is mentioned again and also associated with his anxiety.
http://i.imgur.com/04o0zC8.jpg "When the whole Civil War thing kicked off and the Super Hero community was choosing sides [...] having the Sentry on your side would have guaranteed victory. [...] As the Civil War raged the Sentry paralysed with indecision, chose to sit it out on the moon."
I find this and the many aspects of it quite interesting, so I'll leave it here.
Some Hulk fans like to think, that Sentry's aura was calming the Hulk down during their fight. That was not the case. The story clearly gave that away and so does this handbook.
http://i.imgur.com/bnOq5nY.jpg "By the '50s one small serum sample ended up in the science labs of Midtown High School (Its Health and Safety Record regarding Science projects was notoriously lax - years later another pupil, Peter Parker, would also suffer a science-related accident.)"
Funnily enough Sentry got his version of the Super-Soldier-Serum from the same lab, where Peter Parker became Spider-Man years later.
http://i.imgur.com/fdkpYl3.jpg "[...] because of his illness he'd actually become the Void [...] Luckily Reynolds created the Sentry subconsciously, driven by his love of comic books and his unquenchable desire to do good [...]"
This got also already covered up to some extent in this thread: The idea, that Robert Reynolds first became the Void and then the Sentry. In case that's confusing, I'll try to explain it quickly...
Robert is a schizophrenic and as such he suffers from delusions (a delusion is a strong belief / a strong conviction, that something is the case, even though it really isn't).
In Robert's case, he believed to be an evil boogeyman. He went on to rob a bank under the disguise of the Blue Buffoon. But deep down Robert was still a good guy. So in order to stop himself from doing bad things, he had created the Sentry (subconsciously).
The Sentry fought and defeated the Blue Buffoon. The Blue Buffoon disappeared and the Sentry transformed back to Robert.
However, Robert was still schizophrenic and as such he was also suffering from hallucinations. He was seeing and hearing things, that were not really there... Like for example a dark, evil boogeyman called the Void, and unfortunately for Robert, his powers made the Void real.
I know what this is about. My advice would be to not listen to "that" guy, regarding the Sentry. Don't listen to him, don't engage in conversations with him and for the love of God, Allah, Tom Cruise, or whoever you pray to, don't do anything, that would invite him over here to spit out all the nonsense about the Sentry, that he seems to spit out on the other board.