So outside of Mark 1-7 and 42/43 all the others had very limited screen time. I think the issue is everyone went in assuming it's one thing. Makes you wonder why someone didn't mention ahead of time that maybe people should not get their hopes up...hmm. Oh well.
Hulkbuster didn't have limited screen time, and it was arguably in the best sequence of the film. Anyway, the issue isn't just time on screen, it's that the 45 does nothing new and basically has no purpose other than looking cool. Maybe we'll see something new from the 45 in another film, but at this point it's pointless. Every HPP suit, regardless of how little you saw it offered something unique that the prior armors did not.