As to the 4501 MTH tenders being too small,4501's original tender was smaller and the green MTH version reminds me of that.It was around 1973 that 4501 got her current larger tender that was from a scrapped Central of Georgia 2-10-2. Hopefully MTH will recognize this and do the silver smoke box version like she had with the smaller tender.. https://www.flickr.com/photos/lionelkid18/6091446685
Considering Lionel used the silver smoke box when they did the model of 4501 back in 1992, I wouldn't be surprised if MTH did as well.
As far as their tenders go MTH-wise, they feel like an odd fusion of the original short tenders and the current elongated one. It's not too bad, but it would've been nice to get the current large ones. Kind of like it would've been nice that the NKP 587 one in the same catalog got the Berkshire tender like the current prototype.
I'm also curious if they give the 4501's scenic rail fan passenger announcements, not all too different from how they did with their rendition of Western Maryland #734.
Not to mention give them prototypical whistles!