Re: What direction would you have liked the third act to go in?
Harada was a more interesting character than Viper, so I'd pick her if we're cutting someone. Also, Viper is essentially just a face behind the technology with no motivation, so you could cut her with no impact on the plot.
Having seen this a few times now, I'm happy enough with how things came together for the end, but the final fight is ridiculous. If they just cut the super-sized robot and put Yashida in a regular sized suit of armour. There could have been a far more restrained confrontation in keeping with the rest of the film, and we could have finally had Logan a proper sword fight there as well, instead of him waving that giant, flaming one about.