It would be a huge plus to be able to add funds to your MS account through Paypal or a credit/debit card.
I know an Xbox Live gift card can be purchased and funds added via redeeming the gift card, but this just includes more steps than needed. What makes little sense is that if you purchase a gift card through the MS store, you have to wait for the gift card to be mailed to you. Why is there no option to have the code emailed to you, such as other sites provide? Depending on the site, you receive the code almost instantly and MS doesn't have to pay the postage.
I want to be able to deposit funds into my account (right from my Xbox One preferably) on a fairly consistent basis without jumping through a lot of hoops so that they are there and ready to use when I want to purchase a game. It's nice to have a little bankroll in place to help take the sting out of a $59.99 purchase and there are going to be a lot of those purchases coming up this fall.