Beep Beep! ArchKnight AQ / ED
Regarding the reason to choose swords, mostly down to aesthetics now, IMO. Some classes are better off using the class weapons as some skills require them, such as Merc's/Tact's Double Strike. This was lifted on Static Smash so allows users to use a sword now.
I believe the old system was way too restrictive, there is a great deal of really nice looking gear but that would hinder the use of it with the old stat system, items like Jade Magnum (12 Support IIRC?) and Chars Club (10 Dex/15 Tech IIRC?) were great for specific builds. Now everyone has a chance to use every weapon how ever they wish. I believe this was a step in the right direction.
I cannot immediately see an issue with this however, it does make every weapon more versatile because a specific class is not so much singled out of weapon types now, everyone gets to enjoy what they like.
Although in some ways fixed stats were great, looking at YOU Caden's Curse, 25 to Tech!, in some ways it was bad if you wanted that specific weapon for use on a Supp TM you couldn't really use it well.