We heard a little while ago that Bulkhead originally had been intended to be Ironhide in the Prime series, but the creators thought that the final character design for him was more reminiscent of Bulkhead than of Ironhide and thus decided to change him to Bulkhead. It's occurred to me that if this is true, then the change in character might well have prompted some changes in others members of the main cast, namely Arcee, Jack and Miko. Because Bulkhead does not have as close a connection to Optimus and is not as prominent as Ironhide, he became simply the 'muscled soldier' of Prime's team, possessing the brawn of Ironhide but not his age, experience, rank and long-running, close friendship with Prime. Hence removing Ironhide from the Autobot cast could have promoted Arcee in terms of importance in the team in an attempt to fill in the 'second-in-command' position that Ironhide would conceivably have filled. She became the 'trusted lieutenant' to Prime instead. This would explain her "special bond" with Optimus and being his "go-to girl" from her bio description. They're the vestigial remains of Ironhide's position that Arcee inherited. I also think it's a possibility that had Ironhide been used, Jack may well have been his human partner, and Miko may originally have been intended to be partnered with Arcee. But with the dropping of Ironhide in favour of Bulkhead and the resulting prominence in Arcee's position on the team, the producers may have decided it was more suitable to pair Jack up with Arcee instead, and Miko was paired with Bulkhead. The Sari pink hair influence on Miko may well have been the result of her being partnered with Bulkhead, making them both homages to the Animated series. And the partnership of Arcee and Jack, along with Arcee's rise in importance in Prime's team, may have lead to the decision to give Arcee a stronger and more 'masculine' colour of blue as opposed to a more traditional female colour such as magenta pink or purple (which may have happened had Ironhide been kept as part of the Autobot cast). Just some thoughts I had. What do you all think? And could the loss of Ironhide from the main Autobot cast have triggered any other changes in the show and its characters?