It is a classic, young go-getter vs. the grizzled older veteran, youth vs. experience, up and comer vs. the champ.
But 2 things that stand out to me is that Weidman has been sidelined for quite a long time, his last fight being on 12 july 2012, and Anderson is notorious for his ability to stay calm in some tricky situations and thriving off the mistakes of his opponents.
The inexperience, coupled with the lenghty break from fighting, take that and put it up against someone like Silva and it seems like a complete shot in the dark to bet on Weidman.
Sure Silva will lose eventually, age will catch up to him and he will get slower, weaker etc. But i do not think Weidman is the guy that will beat him