I have not seen a single logical argument for a limit to the number of discs you can carry.
^^2nd this.
Pros for unlimited discs;
-Obviously the bigger selection of discs for
-FH, BH, Tomahawk, Thumbers, Rollers, Putts
-Wind Variation
-Reserves for possible lost plastic
Cons for unlimited discs'
-Takes a while to decide a disc to throw
-More fatigue from carrying more plastic
-May cause you to overthink a shot
But...
none of these are good enough to sway my opinion either way. Personally, I carry anywhere from 8 discs on a short course, to 14-16 on a longer, more technical course. League/Tourney rounds always add a disc or two as backups. Average I carry per round is 13. Familiarity of a course can weed out a disc or two, knowing that I won't use certain discs at all. I know all the discs in my bag like the back of my hand, so if I were to carry 30 discs I wouldn't have any problem finding the proper disc and tossing it within an allotted time.
I'm not exactly sure that allowing a player to carry more discs is necessarily an advantage. You still need excellent technique to make excellent shots. Its not like a disc is going to make a gap, just because its a __________. And just because there's a limit on clubs in ball golf shouldn't have any bearing on a limit on discs. The limit of 6 balls in ball golf is a little different, as each ball is supposed to do the same thing. So the only way this rule could translate into disc golf is that you could only carry a certain amount of a certain mold, which still doesn't quite translate because of wear levels, plastics, weights, etc.