P30 only lasts for a very short time, it is not suitable for controlling B.O.W.s. Wesker had to constantly up the dose to Jill via his remote device. OK for one individual perhaps, but not exactly suitable for armies of B.O.W.s you are sending out into the field.

Another reason is that Jill was being used as a test subject for P30 to see what adverse effects it had on the body and how long she could last before her intelligence degraded. Tyrants need high intelligence to follow orders so this is why P30 would not be suitable as it would be eroding their mental capacity.

Thirdly, P30 was discovered by accident when Progenitor Research resumed in 2007. Progenitor was highly restricted at Umbrella and only employees with Level 10 clearance had access to the site in Kijuju where it was produced. The reason Wesker had to go all the way to Africa to get it is because that is the only place where it was. The Africa location was top secret, and Albert only learned of its location after he killed Spencer in 2006. This small plot point is why the whole of RE6 is set in Africa.

Spencer had patience to find the Stairway to the Sun flower because he knew it existed and he knew of its power thanks to Henry Travis' book. He did not know of the Plaga or its properties because until then no one knew it existed, not Umbrella, not Wesker, not Ada's organization or the rival company, no one. The plagas were discovered by complete accident in rural spain by a religious cult. It was only after this when the powers that be learned of its existence did they try to get their hands on it.

I feel Wesker was unlike his former self in this one. Or to say he'd be his usual self for a few seconds, gloating and acting out his god complex, then he start preaching like he believed he was a messiah or some desperately need savior. I'd find it more believable if they said that the Wesker in RE5 was really that Alex Wesker/Wesker 12 with plastic surgery than him being the real McCoy.

Common fan theory with this is that he became kind of unhinged after realising he was a product of an experiment all along.

Comparable to a certain S-class soldier in Final Fantasy finding out that he was a product of Jenova...

Anyways, Im curious if anyone has thought to question the whole immunity thing with Jake Muller, considering as he's stated to be Albert Wesker's son. Albert wasn't immune to the first viral injection he applied to himself, he was compatible with it. He was likely resilient to viruses with a progenitor base or weaker, after the fact(but not completely, as he suffered effects from it later, requiring the serum).

The whole Wesker Project would be rather pointless if the subjects were immune to Progenitor, wouldn't it? There would be no progress in evolution, if the intention was "power". I suppose if you wanted to filter out the rest of the species with bio-warfare then those persons would survive as newly immune race, but useless as weapons themselves.

I would think Jake wouldn't acquire Wesker's immunity to viruses, unless he was previously experimented on prior to taking the C-virus "supplement", because his physical looks imply he would be born before 1998(80's), before Wesker's injection. Then again, a possible requirement of truly being compatible with a progenitor-based virus(im assuming C-virus is, but I personally think it's directly derived from G), may be that you have to suffer a mortal wound and "die", temporarily. Much in the way V-ACT worked, but not exactly?

Not unless Capcom is just completely ignoring specifics...

Paul covered it for the most part. Wesker already had immunity to the virus before his injection from Birkin. That was the entire point, was that the Wesker children had superior DNA that would be the closest matches to bonding with the virus and not cause them to mutate like all the others did. Yet, most of the Wesker children still failed in this test, Albert was one of, or the only one to actually succesfully pass the test so to speak.

Jake simply inherited those same genes which would provide the anti-bodies to the virus much like if Jill or Sherry had a child, those children would inherit the anti-bodies to the T-Virus and G-virus respectively. Now given Jill and Sherry's anti-bodies were not natural and were created through innoculation to the virus' post infection, but, still the point of giving those genes to their offspring.

Notice even when Jake is doing all his crazy melee's, he's still not doing super human stuff like Wesker. It's more just top physical fitness of peak human condition which was the goal of the wesker children project. PG-67AW simply enhanced those abilities to super human levels.

So all Jake inheritied was Wesker's original DNA/Blood which makes him have immunity to the virus, a good chance at bonding with progenitor, and peak human condition which allows him quick reflexes and performance.