The Foot Mystics
 

Here's a question that I've pondered for awhile. I know that the writes and such prepare a season or two before for what they're writing. But do you think that the writers planned how the Foot Mystics would evolve even from season 1 (Return to New York) to the heralds of the one true Shredder in season 5?

hmmm good question... I remember the encounter from return to New york and then we don't see much of them until Karai's takeover (When they trick Bishop into getting them that amulet).
I think maybe they just started out as a really awesome obstacle for the guys to go through to get to Shredder but that whole amulet control theory was pretty well tied together so I'd say they probably had something in the back of their minds.

They were so much more powerful in season 5 than they were when the boys faught them on their way to the top floor. The guys could barely handle them with their inner chi but they defeated them earlier without the chi.

Perhaps the mystics gained more power when they were released from karai's control

The mystics gained more power when freed from Karai's control (I'd imagine anyway) plus they probably put more effort in when fighting to revive the true Shredder.

Also it was Splinter who really defeated the mystics in Season 1, not the TMNT themselves, so that might also be part of it.

Not sure that it was planned from the beginning, but it was probably planned from at lastest when they started work on Season 4 (probably mid-way through production of Season 3).

Someone sould find out for sure. I doubt they had season 5 in mind when they started off. Since season one and some of two was based on the comics and season 5 was not, it was probably something they decided on about halfway there.

They definitely were stronger after the amulet was destroyed.
Splinter took out the sword of Tengu and blasted them all away using the element facts against them! In season 1
Anyway it took a lot more then that to beat them later, even with all those mystic powers it took a bit in season 5