Let's say the spaniard accent and the Argentinian one.
I friended you Comandante so I could send you some suggestions on books to learn Spanish that are based on English.
Comandante I do believe you are probably right. I bet there are cultural factors as well at play.
The great thing though is that you know ENGLISH and the references for Spanish in English are are fantastic! If your English is advanced I could turn you onto some great books about how to learn Spanish.
I think the problem is not the accent at all but the large amount of slang between our countries. We (Argentinians) also use another 'person' in our vocabulary to conjugate verbs, "vos".
I think you have no option, because there are lots of different accents when talking spanish. In Spain itself for example, we have lots of different accents. So, if you have been studying standard spanish and you go to Andalusia, you won't probably understand a word. That's because you have to get used to accents, talk with lots of people with different accent. Like in english, I presume!
You'll be able. Sure. But I guess it's better if you learn a standard accent because everyone will be able to understand you.