Unless you're building the whole new product that serves a different purpose, and is only influenced by Basecamp - in that case, it makes sense.
It doesn't do some of the things the existing Basecamp does.
It does new things the existing Basecamp doesn't do.
It's a new product with new ideas about what's important in a product like Basecamp. It's not the same as today's Basecamp, but it's still familiar to the millions who've used Basecamp.
Basecamp has been awesome for a wide range of users, but we're seeing other folks taking a stab at this space (e.g. https://trello.com/) and eventually someone is going to come up with something that is all around better for the average user. Why wait for the inevitable?