WebApi feels great and respects the HTTP spec (PUT, DELETE, UPDATE, POST,GET) and even the OData spec is compliant and after all, it's very fast to implement WebAPI and OData.
The .Net (mostly Asp.Net) is evolving fast for technologies like SignalR en OWIN.. And actually that's great.
You could still use webforms if you want, but i woudn't recommend that.
Most people hate change, but considering the (positive[subjective]) changes, they have done.. I think it's awesome and liberating.
OWIN has a improved authentication implementation, which has been a long requested feature for Asp.Net. For example, when you wanted to customize the Authentication implementation (don't remember the interface), you had to implement all of the methods (ForgetPass, EmailPass, ...). OWIN fixes that also (which was hard because of their former implementation)!
The only way it seems like more hassle/mess, is because there are more DLL's being imported, but i don't care because i know the reason behind it :)