I own a first gen iPad, and I can tell you it won't be the same.

Apps will slowly stop working, and updates will be restricted to newer firmware only, meaning my only option is to delete the apps that I had been using and paid for... or heaven forbid I need to do a restore and get all of my apps back. Then it's just a lottery of luck on how many I'll be allowed to download, and that number will decrease with time.

I can understand dropping support for legacy products, but I've only had the thing a year and a half or something.