Understood on 100 point armor builds but the year makes a huge difference. Is this just in general, or are you building for a specific scenario?
Your initial question is a 100point armor build viable for the germans? Just an opinion but, Yes. On earlier scenarios as you go up it will get harder and you will have to be more creative lets say 1943 and up (the allies just have good cheap stuff). The 35 pt Panther(1942 I think) a brummbar(1943) and a Hetzer(1944) are all good. The Brummbar is priceless against infantry and is fairly cheap 22.