ASP.Net MVC to ASP.Net core MVC migration Points to consider:

1) There are no concepts of dependency injection into the constructor, once singleton class instances are being created and being used. As there are no dependency injection concepts as such so there are concepts of service lifetime for example AddSingleton or AddScoped or AddTransient.

2) Assembly version mismatch is inevitable and most common concern between System.Web.Pages and System.Web.Pages.Razor because syntaxes differ between each version.

3) Data seeding API is different than of Entity Framework Core.

4)Middleware pipeline or concepts of filters are not there.

So there are lots of disadvantages but comparatively faster processing than .Net code with tons of Middleware pipeline.

5)As we all know ASP.Net MVC provides web application framework for windows centric development but whereas core provides cross platform compatibility with the introduction of Kestrel server.