Thats all good ideas. but i still think that season three will just be a 3 way war between the snakemen ,skeletor and the masters.cause in season 2 it was more focus to the snakemen of course.
now that the intro to the snakemen is done now a true war can begin. but if you remember that both the well of darkness and hordaks sanctuary were destroyed. which means there are only 2-3 things that can open a dimensional portal. 1. the sorceress. 2. the oracle. 3. Gwildor and the cosmic key. but i think that hordak coming back will be something of the end of season 3 or the start of season 4 like what evil lyn and cobra khan did in last stand about making an alliance.
Man-at-arms would be a snake man for 1 or 2 seasons just to prolong that story and it gives more and more time to build the relationship with fisto and teela, though fisto would be her real father that information would never surface in the series except outside the show to the fans. in the end Duncan would always be teela's father. the only time teela would know the truth is when she becomes the next sorceress of greyskull. but mainly keep duncan out as more of an act of redemption for fisto to prove to his brother he is not a coward. and when duncan returns all hard feelings between them will be gone.
Faker would make an appearance now after the start of this large scale war. faker would be used as an infiltraitor at first then over time i could see skeletor using him against he-man and the snakemen.
also in season three we will see more introductions from the classic line like mentioned clamp champ. maybe even ninjor or jitsu. for the gun nuts. rio the snakeman hunter would make an appearance. Also in my personal opionion i think it would be a great time to bring in Granamyr. despite what the board knows of eternia. Granamyr is the oldest of all dragons on eternia lets say 10,000 years old? from the somewhat quiet icy volcano of darksmoke. Granamyr has amassed hordes of treasures and items from all of eternias past. one of which is the second stone of protection which is used in she-ra's sword. the stone itself allows the person to wield the stone to talk to any creature. which then TA DAH! granamyr can talk. Granamyr would tell the secrets of the snakemens magic and give clues on how to turn man-at-arms back.
just spliting the paragraph. also Chadzar,Azdar,Belzar make a return as there group has been taken over by a new alpha of the group. Megator. later on megator would kill them but obviously would not show them being kill but show off the various items they wore on large dirt mounds.
but thats my idea. i like what you guys had.