I'm sure it has been stated before but a migration tool to move from SMF to XenForo would be great! Especially if it was native like the large list XF already has.
From my perspective, I'm a barely web savvy forum admin who wanted to upgrade to a premium forum software and XF fit the bill. I manage 4 sites that all use SMF and these are the ones I'm gonna be looking to upgrade. I'm working with someone on here to convert my SMF to XF via way of PHPBB3 or something but it was almost a no sale for me which would have been close to $460.00 loss of revenue plus yearly 160.00.
Food for thought.