I actually prefer Sm4sh's For Fun taunt parties over Brawl's Basic Brawl ones. The very existence of For Glory creates an answer for those who can't stand taunt parties, something Brawl had no answer to at all and I've gotten quite a few friend request things (whatever term the Wii U uses for them) from FF taunt parties which is another feature Brawl lacked. The only thing Brawl had over Sm4sh imo was stage selecting but I'll gladly take random stages over Temple and FD over and over and over again @.@
Indeed the combination separation and connectivity does make Smash 4's Taunt-Parties superior in the regard, however, at the same time, Taunt Parties are more "fragile" because now you have to hit your own partners every so often to prevent yourself from getting banned, and if they don't understand your purposes, they could either overlook this rule and get banned themselves, or attack you because they thought that you were attacking them.
As for the stages, they could just make it where the more a stage has been chosen, the lower the percentage of it being selected would be.
So, for example if there was a 3/1 decision for Temple, it would start off as 75%, but as the matches went on, it could be a 3/1 with only a 25% chance, therefor making it 25/100 (if coded in such ways), or 25/50, and thus allowing other stages to be chosen