Defensive and Offensive Advantages?

Is there any way to have territories that have defensive and offensive special abilities?

I'm not sure what you mean by that but I think the answear is no...if you mean do you get more men from owning certain territories than yeah just look at the mini map or legend...

How about like an extra dice? For like capitals or something?

it would have to be programmed as a new option. personally i would prefer that the site not get this option because I see this site as a mainstream risk site that doesn't stray too far from the original. There already is a risk site out there that has this option, landgrab.net. i don't play there because the maps are beyond awful, the interface is ugly, and it has way way too many options that make it hard for new players to compete and they almost make the game unrecognizable as risk if you use all the options in one game. But if this option is important to you, i suggestion you check that site out.

Not every site can fill every need. If this site isn't doing it for you then try the next one. But there's no sense in changing this site to be exactly like that other site cause then it wouldn't fill my needs and the people who share my preferences. It's important to have multiple sites that cater to various preferences.

You can also play on both sites and get the best of both worlds.

BTW, on landgrab you can have leaders which give you an offensive advantage and fortresses that give you a defensive advantage.