Seeing how Iran is a legitimate country you can't hardly delegitimize it though can you? If you don't have the ability to talk to your enemies then you have zero possibility of ever having anything good come of the relationship.

When the only goal that your enemies have is to kill you and they don't mind dying in the process, I see no starting point for any kind of relationship.

I think it would be advisable to be speaking with a world power that can have thousands of centrifuges spinning , and any deal you can work out to slow that progress down (even if its just for a few years or a decade) is a good thing.

If you think that Iran is going to slow down their quest for a nuclear weapon because of talking to the US, then you are sadly mistaken. Every day they chant in the streets "Death to America". Is there some reason not to believe what they are telling us?

Of course by the time the deal nears expiration thing in the middle east could (and will) change so no deal is going to last forever anyway.

No it won't. By that time, Iran will have a nuke so things will be much worse. And we will all be able to thank Obama for that.

Now on the other hand - doing stupid things like a Muslim ban legitimizes their reason to hate us.

First of all, they hate us anyway. This was Obama's philosophy: maybe if we are nicer to our enemies, they will hate us less. Secondly, it was not a Muslim ban. It was a 90 to 120 day moratorium on people from 7 middle eastern countries with a known history of terrorism from coming in to the US. The reason is that we need to find better ways to vet them. Oh, BTW, this list of 7 countries was put together by none other than Obama.