Not disputing it can destroy Dracula. However Barlowe runs Ecclesia and he would know that it's the only thing strong enough to destroy the seal.
No reason to build something that can destroy Dracula himself when all he needed was to destroy the seal, which is obviously much weaker than the Demon Lord of all Darkness.
Sure, sure, if the seal was keeping Dracula inside, then it was stronger. But was stronger than a WEAKENED Dracula. The seal didn't need to be stronger than Dracula, it only needed to be stronger than Dracula when he's dead.
So, again, no reason for Barlowe to build something that can actually destroy an awakened Dracula when he needed only something strong enough to destroy the seal.
B) Barlowe is corrupt and has "chaos" in his heart - which he states mankind having is the reason for Dracula's perpetual return (which is substantiated by OOE and other games)
And, of course, Shanoa, not being drunk with evil, understands that mankind desires for no such thing. Barlowe is not even making sense here.
C) If Dominus had corrupted him, why wouldn't he just lie to Shanoa in order to break the seal - which he initially told her was the vessel for Dracula's soul? Why tell her AS she was about to break it? It makes no sense
I'm not sure if I understand what you mean here. There is a LARGE piece of dialogue before this, and Shanoa makes it quite clear she's not doing it because she already knows what's up - thanks to Albus. Barlowe loses his posture because Shanoa will not comply. He wouldn't lie because there is NO WAY he can lie here.
D) He outright states that Ecclesia's purpose is to revive Dracula
He also states the mankind wishes for Dracula's revival
Again, he's not making any sense and is delusional at this point. And even if he weren't, who is to say that he hasn't repurposed Ecclesia right now? He's the founder. He can do whatever the hell he wants at any point in time. Who is to say he did NOT think like this before being corrupted?
E) Shanoa accuses him of being corrupted by Dominus and he point blank states NO
I don't believe he's saying "No, Shanoa. I'm not corrupted". I believe it's more like "No, Shanoa... How could you let me down now?";
And again: If you were corrupted, would you say "YES YES I'M CORRUPTED YES"? Of course not. Barlowe thinks these ideas are his, and not creations of Dracula's influence. He thinks he's doing the right thing.
See the battle with Albus. Albus NEVER recognizes he's corrupted
while corrupted, and well... He quite clearly is.
F) Why use Shanoa/ Dominus when a simple sacrifice would do?
- He didn't want to sacrifice himself,
- He didn't know if a normal sacrifice would be enough but tried anyway,
- He knew Shanoa without Dominus wouldn't have been a strong enough sacrifice,
- Because story
He didn't want to sacrifice himself - yet he happily did it when he couldn't obtain Dominus.
He didn't know if a normal sacrifice would be enough but tried anyway - I give you this one. It seems to me that he was ony sure it'd work when he was right about to do it.
He knew Shanoa without Dominus wouldn't have been a strong enough sacrifice - Makes no sense. If your hypothesis is correct, then Dominus was designed to break the seal, and not kill Dracula. If it was designed to break the seal, then a sacrifice wasn't even needed at all. He only needed someone with an innate ability to use glyphs - Shanoa - so he'd not have to consider if Shanoa was enough or not. Proof of this is that they fight each other because Barlowe wants Dominus so he can use it himself. All that was ever needed was Dominus, therefore a sacrifice was never even considered.
Because story - Oh well.
As I stated above, Barlowe would not have wanted to sacrifice himself. He crawls over to the seal as a last ditch effort and self destructs. It still required a large amount of power to destroy this seal and Barlowe is very strongly skilled in magic. Therefore Shanoa trying to break the seal without Dominus isn't something that would have been possible.
And as I said up there: If your hypothesis is correct, a blood sacrifice was never even considered. All that was ever needed was Dominus, and since Shanoa was supposed to be the only one able to use glyphs, she was needed. Once Barlowe noticed that he could too use Glyphs like Albus, Shanoa became useless and he tried to rip the glyph from her by force.
Important of note: Dominus does kill it's user. But only because Dracula's power is too much to bear, and not because "sacrifice". Each of the Glyphs, when used separatelly, consume Shanoa's life. This is a side effect of Dracula's power, and not "intended so the user is sacrificed".
Why otherwise would Barlowe fight Shanoa?
To take the Glyph from her and use it himself.