Was Noah a Weak Personality?

Yes, we know God chose him. God also chose Moses, a very uncharismatic speaker. As he stated himself.

God doesn't necessarily chose strong personalities.

The most probable reason why Noah got drunk is, he had not come across fermented grapes, aka wine, before the flood. Perhaps the climate made alcohol turn quickly to acetic acid with a second fermentation, perhaps grapes were a new crop, perhaps drunkenness had been a thing and pre-Flood just men had been teetotallers as well as vegetarians. So, Noah had never experienced the effects of alcohol.

But it is also possible he was grieving very hardly over the loss of his wife, or simply trying to keep chaste when every woman left alive was either a daughter in law or a granddaughter or descendant.

There are different definitions of weak personalities though. It's not just about not avoiding sins, it's sometimes about not being stepped on by others. In this respect, there is no shame before God in being a weak personality. At least not if they are very sneaky and exploit the weakest moments - as Ham did.

That Noah could have been a weak personality in this sense, the kind of man Pierpoint Morgan or Vanderbildt (whoever of them wrote the book on getting successful and successfully sold it) and possibly even Thomas Arnold (the one with "muscular Christianity" not his poetic son) might call a weak pesonality, is brought out by another fact. He had his sons at 500, those who came with him on the Ark. Had his marriage been delayed for some centuries? Had older sons of his been taken away by pre-Flood versions of the infamous CPS? In either case, we would deal with malefactors of his who had exploited some kind of weak (not necessarily sinful) moments, to step on him as some step on a weak personality.

The repeat offender in this respect was Ham, a son of his. Putting "weak personalities" in "their place" is the essence of the sin of Ham./HGL